Health, Fitness & Body Calculators

Body-mass index for adults with the WHO reference bands shown neutrally, plus the substituted formula step by step.

US-style BMI from pounds and inches using the ×703 conversion, with CDC adult reference ranges.

BMI with reference context written for women — what the index can and cannot say about female body composition.

BMI with male-specific context — why muscular men often read 'high' and when waist measures matter more.

BMI with evidence-based context for 65+ — why slightly higher values read differently in later life.

BMI plus an honest read-out of why the index misclassifies muscular athletes, and which measures to use instead.

BMI against the WHO Asian-Pacific reference points (23 / 27.5), which differ from the standard bands.

BMI using the lower Indian cut-offs (23 overweight, 25 obesity) adopted from ICMR and Ministry of Health guidance.

BMI Prime — your BMI as a ratio of the 25 kg/m² reference point, so 1.00 means exactly at the upper reference.

Corpulence (ponderal) index kg/m³ — the height-fairer cousin of BMI for very tall and very short adults.

Trefethen's 'New BMI' (1.3 × kg / m^2.5) which corrects the classic formula's bias against tall people.

Enter a BMI value and height to see the corresponding weight, plus the full weight span of the WHO reference band.

UK-style BMI from stones, pounds, feet and inches — no mental conversion needed, NHS reference bands shown.

Estimates full-body-equivalent weight from the published segment-weight table, then computes adjusted BMI.

Clinical dosing-reference weight: IBW + 0.4 × (actual − IBW), used by pharmacists when actual ≫ reference weight.

The 1974 Devine formula (50/45.5 kg + 2.3 kg per inch over 5 ft) — the standard clinical dosing-reference weight.

Robinson 1983 modification of Devine (52/49 kg base, 1.9/1.7 kg per inch) — a gentler clinical reference line.

Miller 1983 reference weight (56.2/53.1 kg base with 1.41/1.36 kg per inch) — flattest of the classic IBW lines.

The 1964 Hamwi method (48/45.5 kg + 2.7/2.2 kg per inch) still common in US dietetics quick estimates.

The 19th-century Broca reference (height in cm − 100) and its modified form — where 'ideal weight' formulas began.

The Lorentz reference weight (1929) — Broca refined with a sex-specific correction, still quoted in European texts.

All four classic reference-weight formulas computed side by side, with the spread between them made explicit.

Resting energy via the equation the Academy of Nutrition and Dietetics rates most accurate for modern adults.

The classic 1919 metabolic equation in its 1984 Roza–Shizgal revision, with a note on when it over-predicts.

BMR from lean body mass (370 + 21.6 × LBM) — the equation of choice when you know your body-fat percentage.

The 500 + 22 × FFM equation sports dietitians prefer for trained athletes with measured body composition.

The weight-only WHO/FAO equations by age band — the basis of many national dietary reference values.

The 2005 Oxford re-fit of the world BMR database — corrects Schofield's known over-prediction for many populations.

Resting energy for women via Mifflin–St Jeor, with context on cycle, contraception and menopause effects.

Resting energy for men via Mifflin–St Jeor, with the +5 constant and what actually moves the number explained.

Resting energy after 65 with honest error context — why equations drift with age and what matters more than the number.

Resting metabolic rate with the BMR-vs-RMR distinction actually explained, not blurred.

Metabolic intensity — resting kcal per kg of body weight and per kg of lean mass, a fairer between-person comparison.

Resting energy in kilojoules — for Australia and New Zealand where food labels and guidelines use kJ, not calories.

Energy spent digesting — TEF from your macro mix using published per-macronutrient ranges, not a flat 10% guess.

Four published resting-energy equations on the same inputs, with the spread shown — see how much 'your BMR' really varies.

The Hodgdon–Beckett tape-measure method used by the US Navy — body fat from neck, waist (and hip) circumferences.

The three-circumference Navy formula for women (waist + hip − neck) with female reference ranges and measuring tips.

Two-circumference Navy formula for men (waist − neck) with male reference ranges and honest error bars.

The 2018 two-measurement formula (height ÷ waist) that tracked DXA scans better than BMI in 12,000 adults.

Converts BMI, age and sex into a body-fat estimate via the Deurenberg regression — with its limits stated plainly.

The US Army circumference assessment with the official-standard context — same log formula, Army measuring protocol.

The simple YMCA waist-and-weight formula — body fat from just two numbers, with its accuracy trade-off explained.

Chest, abdomen and thigh calipers → body density → Siri body fat: the standard male 3-site lab protocol.

Triceps, suprailiac and thigh calipers with the female-specific density equation and Siri conversion.

The full seven-fold research protocol (both sexes) — maximum tape-free accuracy outside a lab.

The four-fold (biceps, triceps, subscapular, suprailiac) log-sum method with age-banded coefficients.

Convert body density from any skinfold or hydrostatic protocol into fat percentage with the classic two-compartment model.

The alternative density-to-fat conversion (457/D − 414.2), compared live against Siri on the same input.

Split body weight into fat mass and fat-free mass in kilograms from a body-fat percentage.

LBM via the Boer, Hume or James formula (selectable) — see how the three published equations bracket your lean mass.

The 1966 Hume LBM equation — derived from tritium-dilution body-water studies, still cited for drug dosing.

The 1976 James LBM equation with its quadratic weight term — and the high-BMI breakdown it is famous for.

The direct route: weight × (1 − BF%) — lean and fat kilograms from a measured body-fat percentage.

Whole-body skeletal muscle (not just 'lean mass') via the MRI-validated Lee 2000 anthropometric equation.

Skeletal-muscle percentage with Janssen reference bands by age and sex — where smart-scale 'muscle %' numbers come from.

Litres of body water via the Watson equations — the standard used in dialysis dosing and hydration physiology.

Water as a share of body weight, with the lean-tissue logic that explains why fit people are 'wetter'.

Fat-free mass scaled to height² — the lifter's 'BMI for muscle', with the published natural reference bands.

FFMI with Kouri's +6.1×(1.8 − height) correction so tall and short lifters compare on equal footing.

Fat mass scaled to height² — FFMI's forgotten sibling that separates 'high BMI from muscle' vs 'from fat'.

Body fat estimated from hip circumference and height alone — no scale needed, by design.

BSA via Mosteller, Du Bois, Haycock, Gehan–George or Boyd — selectable, with the spread between them shown.

The original 1916 body-surface-area formula that a century of physiology and dosing tables were built on.

The √(H×W/3600) one-liner — the BSA formula clinicians actually compute at the bedside.

The BSA formula validated from premature infants to adults — the paediatric nephrology standard.

BSA from the 401-subject direct-measurement dataset — common in chemotherapy dose protocols.

The weight-self-correcting 1935 BSA formula used by some cardiac-index and paediatric references.

Mosteller, Du Bois, Haycock, Gehan–George and Boyd on one input — with the dose-relevant spread computed.

Surface area per kilogram — the geometry behind why children chill faster, dose differently and sweat differently.

The 'keep your waist below half your height' screen — simpler than BMI and better at flagging central fat.

WHR with the WHO measurement protocol and sex-specific reference points — apple vs pear, quantified.

The 2013 eccentricity-based shape index that went viral in 2024 after JAMA mortality data — computed properly here.

Waist size normalised for BMI and height — isolates central-fat risk that BMI mathematically cannot see.

How close your trunk is to a double-cone vs a cylinder — the abdominal-fat geometry index from 1991.

Estimated abdominal volume from waist and hip girths — the index validated against glucose intolerance.

Neck girth against the published screening points (37 cm men / 34 cm women) and the sleep-apnoea context.

Your waist vs the WHO and IDF action points — including the lower South-Asian thresholds most tools omit.

Trunk-to-stature proportion — the anthropometric index behind bike fitting, cockpit design and growth assessment.

Arm span minus height — the climber's favourite stat, with what the evidence actually says about it.

Small, medium or large skeletal frame from the height-to-wrist ratio — and what frame size is actually for.

The anthropometric-survey method: elbow width between the epicondyles vs NHANES-derived frame bands.

The clinical reference weight span (BMI 18.5–24.9) at your height — presented as context, never as a target.

Where a male body-fat percentage sits among the ACE and essential-fat reference bands — interactive, not judgemental.

Female body-fat bands with the essential-fat physiology explained — why women's ranges sit higher by design.

Your dynamometer reading against the consolidated age- and sex-banded norms — grip as a health marker, explained.

The modern BMI-anchored reference-weight equation that fixes the century-old formulas' height drift.

Boer, Hume and James computed together — see the spread, and which one your dosing software likely uses.

Research-anchored estimate of drug-free lean-mass ceiling from the FFMI-25 observation — hype-free numbers.

Centimetres to feet-and-inches and back, with the exact arithmetic shown — no rounding surprises.

Three-way body-weight conversion with the UK stone-and-pounds format rendered properly.

UK stones-and-pounds straight to kilograms with the working shown — the format GP letters actually use.

Chest, waist, hip and inseam converted in one pass — for clothing sizes and tailoring across unit systems.

Band and cup from underbust and bust measurements using the modern (no '+4') method, with sister sizes.

Head circumference to US, UK and EU hat sizes — the π division that millinery has used for two centuries.

Hand circumference and length to numeric and letter glove sizes — including why the number is just inches.

Inner diameter or circumference to US numeric and EU/ISO ring sizes with the exact linear formulas.

BMI, estimated body fat, lean mass, body water and BSA from one set of inputs — five validated formulas, one view.

The Tanner mid-parental method paediatricians use for a first estimate — with its honest ±8.5 cm window.

Maintenance energy from Mifflin–St Jeor × activity factor — with the honest ±15% error bar most TDEE tools hide.

Daily maintenance energy for women — with cycle, contraception and menopause context the generic tools skip.

Daily maintenance energy for men, plus what genuinely moves the number and what's noise.

Maintenance energy keyed to lean mass — the TDEE method of choice when you know your body-fat percentage.

The classic TDEE pipeline many older charts and textbooks use — useful for matching legacy numbers.

Cunningham RMR plus per-session training energy — built the way sports dietitians actually compute athlete needs.

Your estimated maintenance intake plus the 14-day verification protocol that turns the estimate into a measurement.

TDEE ÷ BMR — the dimensionless activity index FAO/WHO uses to classify lifestyles, computed from your real numbers.

Answer three concrete questions instead of guessing 'moderately active' — get a defensible TDEE multiplier.

Energy from everything that isn't sleeping, eating or sport — the most underrated lever in daily expenditure.

Energy for a walk by real pace bands from the research compendium — strolling to power-walking.

Running energy by pace from 8 to 16 km/h — and why per-kilometre cost barely changes with speed.

Cycling energy by speed band, with the drag physics that makes fast riding disproportionately expensive.

Swimming energy by stroke and effort — and why technique changes the answer more than any other sport.

Honest numbers for resistance training — lower than cardio during the session, with effects that outlast it.

Hatha to power yoga, measured honestly — yoga's value is mostly not the calorie line.

Trail energy with terrain and pack effects — why mountain kilometres cost double the flat ones.

Skipping is among the densest common exercises per minute — with realistic bout math included.

Erg and water rowing by effort — plus the exact watts-to-calories formula your monitor uses.

Stairs, stepmill and the famous 'take the stairs' arithmetic, quantified per flight and per minute.

Cleaning, vacuuming, mopping and scrubbing as measured activity — NEAT made visible.

Digging, weeding, mowing and planting by compendium values — the workout hiding in the garden.

Ballroom to Zumba by measured intensity — what a night of dancing actually costs.

Realistic elliptical numbers — and why the console's count usually flatters you by 20–30%.

Shoot-around to full-court — game formats change the energy bill more than effort does.

Casual kickabout to competitive 90 minutes, built on player-tracking research.

Singles vs doubles quantified — the court-share arithmetic that halves the workout.

Social rallies to competitive singles — the shuttle game's real intensity, often underestimated.

Batting, bowling and fielding as separate jobs — because a cricketer's afternoon isn't one intensity.

Downhill runs vs cross-country grinding — two sports sharing one word, energetically far apart.

Score your week in MET-minutes against the WHO 500–1000 target — the metric behind '150 minutes of exercise'.

Protein, carb and fat grams from your maintenance calories using the Institute of Medicine's accepted ranges.

A g/kg-anchored high-protein layout (not a crash plan) — protein set by body weight, the rest balanced.

Macros tuned for lacto-ovo eating — with the protein-quality adjustment plant-forward diets actually need.

Fully plant-based macros with the digestibility-adjusted protein dose and the lysine watch-list.

The classic 40/30/30 'Zone' layout and its block system, with the evidence stated straight.

The PREDIMED-style pattern translated into grams — higher fat than you'd guess, and why that's the point.

Moderate low-carb layouts (50–150 g) with the hydration/electrolyte transition facts — not a crash-keto funnel.

Turn any %-based macro split into exact grams for your calories — with validation that the split adds to 100.

Add up any combination of protein, carb, fat, fibre and alcohol grams into calories — with each line itemised.

Daily protein by body weight and training status — the g/kg evidence translated, from RDA floor to athlete range.

The PROT-AGE numbers — why protein needs rise with age exactly when appetite falls, and how to meet them.

Distribute your daily protein across meals at the leucine-threshold dose research says actually triggers building.

Your daily fibre target from the IOM's 14 g per 1,000 kcal rule, with food equivalents to make it concrete.

Your personal free-sugar ceiling at the WHO 10% and 5% lines, translated into teaspoons and real drinks.

The 10% (WHO/DGA) and 6% (AHA) saturated-fat lines for your calories, with butter/ghee/cheese equivalents.

The ×2.5 conversion labels rely on, plus your day against the WHO 5 g salt (2 g sodium) guideline.

The 250–500 mg EPA+DHA reference range against your actual fish and supplement habits.

Your carb range at the accepted 45–65% of calories, with the 130 g brain-minimum explained.

Your daily fat range at 20–35% of calories, with the essential-fat floor most low-fat plans forget.

The full accepted macronutrient ranges for your calories on one screen — the fence within which all sane diets live.

RDA by sex and life stage with the ×1.8 vegetarian multiplier — the nutrient gap that actually matters in India.

Your calcium target by age and stage, with a quick counter for how far dairy and alternatives get you.

The 2.4 µg RDA, who actually runs short, and the supplement arithmetic for vegetarians and 50+ adults.

RDA by sex with a realistic food-gap counter — the quietly under-eaten mineral.

The 3,500 mg WHO target vs your fruit-and-veg reality — sodium's neglected counterweight.

The 400 µg DFE adult target, the pregnancy upgrade, and the food-vs-synthetic equivalence math.

The 600–800 IU RDA, what sun exposure realistically contributes, and the Indian-population paradox.

RDA by sex with the phytate adjustment for plant-heavy diets — immunity's everyday mineral.

Food energy both directions with the exact 4.184 factor and label-reading anchors for AU/NZ/EU travellers.

kcal per gram of any food — the satiety variable behind why some foods 'disappear' and others fill.

How much of your hydration arrives on a plate — the ~20–30% of fluid intake nobody counts.

Distribute the day's macros across your meals by custom weights — front-load, even, or trainer's split.

Total up a recipe's macros and divide by servings — the math home cooks skip and then mis-track.

Scale label nutrition from the printed serving to the amount you actually ate — the ratio everyone eyeballs wrong.

Bridge the EU/India per-100g label format and US per-serving format in both directions.

Energy and UK units in any drink from its ABV and volume — the 7 kcal/g nobody puts on the label.

Build a blender recipe from real ingredient data — see how a 'healthy smoothie' quietly reaches 700 kcal.

From 2-kcal black to 400-kcal dessert-in-a-cup — itemised by milk, sugar, syrup and cream.

Masala chai ka hisaab — milk ratio, sugar and cup size, from cutting chai to a full tumbler.

Cow, buffalo, toned, soy, oat and almond milk compared per glass on energy, protein and calcium.

Exact protein and calories for any number of eggs by size and preparation — whole vs whites itemised.

The ×3 expansion that wrecks calorie logs — convert weights and calories in both directions.

Dry-to-cooked weights for pasta and noodles (×2.25), with the al-dente caveat.

Phulka se paratha tak — calories and macros per roti by size and ghee, from real atta values.

Protein per katori across toor, moong, masoor, chana and rajma — and the rice-pairing math that completes it.

Protein, fat and calories for any paneer portion — full-fat vs low-fat, raw vs fried, honestly compared.

Almonds to walnuts by count or grams — the healthiest calorie-dense food, portioned honestly.

The invisible 120 kcal per tablespoon — daily and monthly household oil math, the Indian kitchen's biggest lever.

Natural sugars per portion across common fruits — with why whole fruit doesn't count against the WHO line.

Cola, juice, energy and sports drinks measured in grams and teaspoons against your WHO daily line.

Map a 16:8 / 14:10 / 12:12 schedule to your real day — timing only, calories deliberately untouched.

Intake vs expenditure as neutral arithmetic — surplus, balance or deficit shown without judgement.

Turn 14 days of logging and weighing into your measured TDEE — the method that beats every formula.

Same weekly total, flexible daily pattern — the weekend-vs-weekday arithmetic done properly.

The real numbers: +0, +340, +452 kcal by trimester — far from 'eating for two'.

The +330–400 kcal lactation addition with the milk-production arithmetic behind it.

Correct your watch's exercise calories with published validation error rates per device tier.

Daily carbohydrate by training volume from the ACSM/ISSN g/kg framework — periodised, not one-size.

In-session fueling by duration — the 30/60/90 g per hour framework with the glucose-fructose trick explained.

The 0.25–0.40 g/kg per-sitting dose, with the anabolic-window myth given its honest size.

Your body's onboard carb tank — muscle and liver stores in grams, kcal and training-hours.

The modern 36–48 h, 10–12 g/kg protocol — no depletion phase, with a day's worth of food examples.

Gel-by-gel race plan from your expected finish time — when to take what, written like a pace band.

Day-long protein schedule including the evidence-backed pre-sleep dose — distribution made concrete.

The 3–6 mg/kg ergogenic dose in real drinks, timed right, with the FDA 400 mg safety ceiling enforced.

The 3–5 g daily protocol vs loading, water math, and who the evidence actually covers.

The honest size of the 'afterburn effect' — 6–15% of session energy, not the marketing version.

Build a real Indian vegetarian day to your protein target — dal, paneer, dahi, soy and eggs itemised.

Which plant pairs make complete protein and why — the lysine/methionine jigsaw with scored combinations.

Estimated due date from your last period with cycle-length adjustment — plus what 'due date' statistically means.

EDD when you know the conception or ovulation date — the 266-day embryonic clock.

Precise EDD from embryo-transfer date and embryo age — the one pregnancy where dating is exact.

Gestational age and EDD from crown-rump length using the Robinson–Fleming dating curve.

Exactly how many weeks-and-days pregnant you are today, from LMP or due date, with trimester placed.

Work backwards from a due date or birth date to the likely conception window.

GA on any chosen date — for scheduling scans, tests and milestones, not just 'today'.

Your personal first/second/third trimester boundary dates from LMP or EDD.

Days, weeks and percent of pregnancy completed and remaining — with the 'due month' framing midwives prefer.

Reconstruct the LMP your provider's dating implies — useful for forms, apps and cross-checking records.

Settle the 'how many months is X weeks?' argument with the lunar-vs-calendar math shown.

Standard EDD plus the realistic twin delivery windows by chorionicity — because twins rarely wait for week 40.

Your estimated ovulation day and the 6-day fertile window, from cycle dates — with the biology stated honestly.

The six fertile days ranked by published per-day conception probability — not just a highlighted range.

The 6–12 day post-ovulation implantation window — when it happens and what it means for testing and spotting.

Project your next several periods from cycle history — a paper calendar's worth of dates in one tap.

Average cycle length and regularity score from your last three cycles — the number every other tool needs.

Doubling time between two beta-hCG draws — the early-pregnancy number everyone googles at 2 a.m., with honest ranges.

The earliest date a test can biologically turn positive — and the date a negative actually means something.

Measure your luteal length from ovulation and period dates — the half of the cycle that matters for implantation.

Estimate when anyone was conceived from their birth date — for curiosity, anniversaries and genealogy.

The studied calendar method (days 8–19 for 26–32-day cycles) — with its real-world failure rate stated, not hidden.

The clinical IOM gain ranges personalised to pre-pregnancy BMI and week — shown as neutral ranges, never targets.

The IOM twin-specific gain ranges — higher and earlier than singleton charts, by pre-pregnancy BMI.

The real arrival-date distribution around your EDD — week-by-week odds instead of one misleading date.

Tally your real day in mg against the 200 mg ACOG/NHS pregnancy line — chai, filter coffee and cola included.

Which fish, how often — the FDA/EPA three-tier mercury framework as an interactive lookup.

Time-to-10-movements arithmetic with the ACOG framing — and the one rule that overrides every chart.

Where an AFI report value sits among the standard bands — translation for a number nobody explains at the scan.

The cm-equals-weeks rule with its honest ±3 window — what the tape measurement at each visit means.

EFW from the scan's AC and FL measurements via the Hadlock equation your sonographer's machine uses.

Median length and weight at each gestational week — the fruit-comparison chart with actual numbers.

The 110–160 bpm band, how it changes by week — and the heartbeat gender myth measured against data.

The BMI class that anchors your IOM gain range and early-pregnancy planning — computed from before-pregnancy weight.

Exact age in days, weeks and months — settling the 'is she 7 weeks or 2 months?' question properly.

Chronological vs corrected age for preemies — the adjustment every milestone chart silently assumes.

WHO median weights by month with the ±2SD band — context for the percentile conversation, not a substitute for it.

The 150 ml/kg/day rule with per-feed breakdown — the arithmetic behind formula-tin tables.

Use-by dates for expressed milk by storage location — the 4-4-6 rules turned into actual dates.

Scoops-to-water arithmetic with the safety rules that actually prevent errors — water first, level scoops.

Total sleep, night vs naps, by age — the NSF ranges with the spread acknowledged.

Age-appropriate awake stretches and projected nap times from the last wake-up.

Expected wet and dirty nappies by day of life — the only feeding dashboard a newborn offers.

Expected grams-per-week by age band, including the normal newborn dip nobody warns parents about.

What most (75%) babies do by each age — the updated CDC checklists with the 'when to ask' framing built in.

Which teeth come when — the eruption sequence with the wide normal ranges that calm 3 a.m. searches.

Two-way conversion with the 4.345 factor — why '12 weeks' and '3 months' are different ages.

The tablespoon-per-year rule and realistic toddler portions — recalibrating adult-sized expectations.

The 16–20°C sleep-safety window and 37–38°C bath range, with a what-to-dress layer helper.

Which restraint stage fits your child's age, weight and height — with the rear-facing-longer evidence.

Baseline hydration plus the ~700 ml lactation surcharge — drink-to-thirst, quantified.

What normal pump output actually looks like by age and session — against the oversupply highlight reels.

Which phase today is — menstrual, follicular, ovulatory or luteal — and what each phase physiologically means.

How late is late? Days overdue against your own variability, with the sane decision tree.

Statistical spread of your last six cycles with the FIGO definitions of 'regular' and 'irregular'.

HRmax by Fox, Tanaka and Gulati — with the spread shown, because the formulas disagree by design.

Simple percent-of-max training targets across the five standard zones — the gym-poster method done right.

Training targets from heart-rate reserve — the method that personalises zones with your resting HR.

Your complete Z1–Z5 table from age and resting HR, Karvonen-anchored — the zones watches try to guess.

The classic 60–70% zone computed — alongside the honest physiology of what 'fat-burning zone' actually means.

Where your morning RHR sits among population and athlete bands — and what trends in it signal.

Your 1-minute post-exercise HR drop against the prognostic bands from the Cleveland Clinic research.

Your usable beats — HRmax minus resting — and why this single number frames every zone system.

The 180-minus-age aerobic ceiling with Maffetone's health adjustments — low-HR base training quantified.

The Borg 6–20 scale mapped to heart rate and plain-language effort — calibrate feel against numbers.

Lying-to-standing HR jump as a recovery/readiness check — the oldest wearable metric, no wearable needed.

Bike-specific zones from threshold HR — built on LTHR, not max, the way cycling actually trains.

VO₂max from your 12-minute run distance — the 1968 field test still used by federations and militaries.

VO₂max from a brisk mile walk plus finishing heart rate — the validated test for non-runners.

VO₂max from 3 minutes of stepping and a recovery pulse — the lab test that fits in a stairwell.

Level-and-shuttle to VO₂max — the multistage fitness test scored the way selection panels score it.

The zero-equipment Uth–Sørensen estimate: HRmax ÷ HRrest × 15.3 — with honest error bars.

Your VO₂max against the FRIEND-registry population bands — fitness-age framing included.

The original 1943 fitness index from a 5-minute step and three recovery pulse counts.

Pace, time or distance — enter any two, get the third, in min/km and min/mile simultaneously.

Project any race time from a recent result with Riegel's exponent — and the training caveat that goes with it.

Target-time splits at 5K intervals plus halfway — with even-split discipline built into the table.

Pace × distance → finish time for any race, with km and mile pace inputs both accepted.

All three pace currencies at once — for reading training plans written in the other system.

What a treadmill speed+incline equals outdoors — the 1% rule and the energy-equivalent pace, computed.

Stride length from distance and step count — plus the cadence math behind the '180 steps' folklore.

Overall pace from run/walk intervals — the method that gets first-timers through marathons, quantified.

The charming marathon predictor: your 800m interval time in min:sec equals your marathon in hr:min.

First-half and second-half target times for a chosen negative-split percentage.

Functional Threshold Power from the standard 20-minute test × 0.95 — with the protocol that makes it valid.

All seven classic power zones from your FTP — the table every structured plan references.

The number that decides who wins uphill — FTP ÷ weight with honest category context.

Physics-based speed from watts: air drag, rolling resistance and gradient, with honest defaults.

Vertical metres per hour from any climb — the climber's currency, with W/kg cross-estimate.

Speed from chainring, cog, wheel size and cadence — gear-ratio truth for upgrades and singlespeeds.

Pace per 100 m/yd from any swim — the universal pool currency, with open-water conversion notes.

Threshold swim pace from 400 m and 200 m time trials — the swimmer's FTP.

Strokes + seconds per length — golf for swimmers, and the efficiency metric your watch buries.

The Concept2 conversion both directions — split to watts to pace, the erg's native arithmetic.

Steps to kilometres and miles via height-calibrated stride — the 10,000-steps question answered for your legs.

How long any distance takes at real walking speeds — with Naismith's hill correction for routes that climb.

Your gait speed against age-sex norms — the 'sixth vital sign' geriatricians actually time.

Centimetres caught → milliseconds, via free-fall physics — the classic lab practical as a tool.

Max consecutive push-ups against age-sex norms — plus the firefighter-study mortality angle.

Plank hold time in context — with the McGill caveat that endurance, not records, is the point.

The standard box-flexibility score with norms — and what it does and doesn't measure.

Jump distance vs body height and norms — the zero-equipment power test combines used before lasers.

Isometric quad endurance with norms — the burn that benchmarks skiing legs and rehab progress.

Personal fluid target from weight, activity and climate — built on EFSA references, not the 8-glasses myth.

Litres per hour from pre/post-exercise weights — the only personal number that makes hydration plans real.

Body-weight loss as dehydration percent with the performance and medical bands at each level.

The exact WHO oral-rehydration recipe scaled to any batch size — the formula that has saved ~50 million lives.

DIY isotonic sports drink scaled to your bottle — sodium, sugar and juice ratios from sports-science targets.

The validated 8-shade Armstrong scale as an interactive reference — your cheapest hydration lab test.

Intake vs output the way hospital charts do it — with insensible losses, the line everyone forgets.

Bedtimes that complete whole 90-minute cycles before your alarm — wake between cycles, not mid-dream.

Going to bed now? The alarm times that land between cycles instead of inside one.

The three evidence-backed nap lengths — 20, 90, and the caffeine-nap trick — timed to your clock.

Your week's accumulated shortfall against personal need — and the honest science of repaying it.

Time asleep ÷ time in bed — the metric CBT-I (the gold-standard insomnia treatment) is built around.

Recovery days and a light-exposure plan from time zones crossed and direction — circadian science, packaged.

Your personal last-coffee time from bedtime and metabolism speed — half-life math applied to sleep.

When low-dose melatonin actually works (hours before bed, tiny dose) vs how everyone takes it.

The anchor-sleep strategy for rotating shifts — protect one fixed block, flex the rest.

How much caffeine is still in you, hour by hour — exponential decay made visible.

Total your real day across coffee, chai, cola, energy drinks and chocolate against the 400 mg line.

Estimated blood alcohol from drinks, weight, sex and time — with the only safe driving rule stated plainly.

Your week in UK units against the 14-unit low-risk guideline — drink-by-drink arithmetic.

What your step count actually burned, weight-adjusted — the honest version of the pedometer number.

Tally your real seated hours against the cohort-study risk bands — and the offset dose of exercise.

A realistic standing-desk schedule from your workday — the ergonomics-research ratio, not all-day standing.

Minutes of midday sun for a vitamin-D dose by skin tone, season and exposed skin — the Fitzpatrick math.

Minutes to sunburn from the UV index and your skin type — and what SPF actually multiplies.

Where your watch's HRV sits among age norms — and why your own baseline beats every chart.

Your daily hours projected over a year and a lifetime — perspective math, judgement-free.

The standard smoking-exposure unit clinicians chart — and the screening threshold it gates.

Time since your last cigarette mapped to the published recovery milestones — the most motivating math in health.

The rupees-and-years bill: pack cost compounded over decades, plus the life-time research figure.

Is this reading a fever? Conversion plus the clinically-used bands and the red-flag list.

Count breaths against age-banded normal ranges — the vital sign everyone can measure and nobody does.

When you can donate again, what 450 ml is as a share of your blood, and the recovery timeline.

Safe ascent profile for a trek — the climb-high-sleep-low arithmetic that prevents most altitude sickness.

The comfortable breath-hold measure used in breathing retraining — protocol, score and what it claims.

Lux targets by light source — how many minutes of which light actually sets your body clock.

Race-free CKD-EPI creatinine eGFR with KDIGO staging — the current international standard equation.

The 1976 CrCl estimate that drug dosing references still demand — with the weight-choice subtlety handled.

Pre-renal vs intrinsic AKI discrimination from paired serum/urine sodium and creatinine.

Calculated osmolality and the osmolar gap — the toxic-alcohol screen hiding in routine chemistry.

True sodium behind the dilution of high glucose — the Katz/Hillier correction DKA management leans on.

AG with the albumin correction that catches the gaps hypoalbuminaemia hides.

Expected pCO₂ for a metabolic acidosis — is the respiratory compensation appropriate, or is there a second problem?

Perfusion pressure from BP — the number ICU targets are written in, with the 65 mmHg line explained.

Rate-corrected QT by the two standard formulas — the drug-safety number with thresholds shown.

The AF stroke-risk score that decides anticoagulation conversations — itemised, with annual-risk table.

The structured pre-test probability score that decides between D-dimer and straight-to-ultrasound.

The five-finger pneumonia triage score behind home-vs-hospital decisions.

HR ÷ SBP — the early haemorrhage flag that moves before blood pressure does.

Systolic minus diastolic, with what wide and narrow gaps physiologically mean.

HR × SBP — myocardial oxygen demand as a number, used in stress testing and angina thresholds.

The oxygenation index that defines ARDS severity — with the FiO₂ decimal trap handled.

Alveolar–arterial oxygen difference with age-adjusted normals — locating the cause of hypoxaemia.

Lung-protective 4–8 mL/kg ventilation volumes from height and sex — never actual weight.

Drops per minute from volume, time and drop factor — gravity-set infusion arithmetic.

When the bag runs out — completion time from volume and rate, the shift-planning calculation.

mg/kg arithmetic with dose-cap handling and mL conversion — the universal weight-based dose template.

The standard weight-based paracetamol and ibuprofen reference table — for verifying, not deciding.

Surface-area dosing as oncology protocols specify it — Mosteller BSA times protocol dose.

Holliday–Segar hourly and daily maintenance fluids — paediatrics' most-used formula.

Burn-resuscitation fluids with the half-in-8-hours timing — and the rule-of-nines companion.

Tick the burned regions, get %TBSA — the rapid estimation chart with the palm rule built in.

E-V-M scoring with the component notation clinicians actually hand over — and the intubation line.

The 1-and-5-minute newborn assessment, itemised — with what the score does and doesn't predict.

The liver-transplant priority score from bilirubin, INR and creatinine — with the sodium update noted.

Cirrhosis severity A/B/C from five parameters — the classification drug dosing references still cite.

Dog-to-human age by the 2020 epigenetic-clock science — not the debunked ×7 myth.

Human-equivalent age adjusted for body size — because a Great Dane and a Chihuahua age on different clocks.

Cat-to-human age by the AAFP/AAHA feline life-stage chart — the 15-9-4 rule, mapped.

Estimate a puppy's grown-up weight from its current age and weight — the growth-fraction method breeders use.

Whelping/queening date from the mating date — the 63-day gestation both species roughly share.

Daily energy needs from weight and life stage — the NRC resting-energy formula scaled by activity factor.

Daily calories for a cat by weight and status — with the indoor-cat reality most owners overshoot.

Convert your dog's calorie need into actual cups or grams using your bag's energy density.

Meals-per-day and per-meal portions by puppy age — the frequency that protects little blood-sugar levels.

Normal daily water for a dog or cat by weight — and the change that signals a vet visit.

Daily raw ration as a percent of body weight, split into the 80/10/10 muscle-bone-organ ratio.

The WSAVA 9-point BCS turned into a guided self-check — the 'is my dog overweight?' answer vets actually use.

The 9-point feline BCS as a guided check — including the primordial-pouch trap that fools owners.

Typical healthy adult weight ranges for popular breeds — a starting point, with BCS as the real judge.

Weight-based reference doses for common OTC-safe meds — strictly a double-check, never a prescription.

Theobromine dose from chocolate type and amount eaten — the emergency triage every dog owner should bookmark.

The core WSAVA vaccine timeline projected onto your pet's birth date — informational, vet confirms.

Daily walk and activity minutes by breed energy and age — the under-exercised-dog problem, quantified.

The age your dog or cat crosses into 'senior' by size and species — when screening should ramp up.

How many litter boxes your household needs — the n+1 rule that prevents most feline toileting problems.

Compression rate, depth and breath ratio for dog/cat CPR — the emergency facts, learned before you need them.

Convert blood-sugar readings between US (mg/dL) and international (mmol/L) units — the most-googled lab conversion.

Convert total, LDL and HDL cholesterol between conventional and SI units with the 38.67 factor.

Convert triglyceride results with their own 88.57 factor — the one lipid that doesn't share cholesterol's number.

Convert serum creatinine between US mg/dL and SI µmol/L using the 88.42 factor — kidney-function units.

Convert between US 'BUN' (mg/dL nitrogen) and the urea (mmol/L) the rest of the world reports — two names, one test.

Convert 25-hydroxy-vitamin-D results between US ng/mL and SI nmol/L with the 2.496 factor.

Convert serum calcium between conventional and SI units with the 4.008 factor.

Convert serum magnesium between mg/dL, mmol/L and mEq/L — three units for one electrolyte.

Convert serum phosphate between conventional and SI units with the 3.097 factor.

Convert uric-acid results between US mg/dL and SI µmol/L — the gout and kidney-stone number.

Convert bilirubin between mg/dL and µmol/L — the jaundice number, in both lab dialects.

Convert serum albumin between US g/dL and SI g/L — a simple ×10, but the one everyone second-guesses.

Convert total serum protein between conventional g/dL and SI g/L.

Convert serum iron between US µg/dL and SI µmol/L with the 5.587 factor.

Convert bicarbonate / total CO₂ between mEq/L and mmol/L — numerically equal, conceptually distinct.

Convert total testosterone between US ng/dL and SI nmol/L with the 0.0347 factor.

Convert estradiol between US pg/mL and SI pmol/L with the 3.671 factor.

Convert serum cortisol between US µg/dL and SI nmol/L with the 27.59 factor.

Convert between transferrin (g/L) and total iron-binding capacity (µg/dL) — two ways labs report the same thing.

Translate HbA1c (%) into estimated average glucose and back — the ADAG-study formula every diabetic needs.

Convert HbA1c between the US/India percentage and the European mmol/mol — the same result, two scales.

Convert medication doses across micrograms, milligrams and grams — the decimal-place errors that harm patients.

Convert liquid medicine doses between mL and spoons — with the warning that kitchen spoons aren't dosing spoons.

Convert vitamins A, D and E between International Units and mass — each vitamin has its own conversion.

Convert electrolyte doses between milliequivalents and milligrams — potassium, sodium, calcium and more.

Convert between drops and millilitres for eye/oral drops and IV sets using the drop factor.

Convert solution strength between % (w/v) and mg/mL — decode '2% lidocaine' into milligrams per millilitre.

Work out how much stock and diluent for any target concentration — the universal lab/pharmacy dilution formula.

Pixels-per-inch from resolution and screen size — the sharpness number behind every 'Retina' claim.

Recommended sitting distance from monitor size and resolution — far enough for comfort, near enough to use the pixels.

The ideal TV size for your room (or distance for your TV) by resolution — THX and SMPTE field-of-view targets.

Solve any missing dimension that keeps an aspect ratio — for screens, video, images and crops.

Minimum legible font/letter height for a viewing distance — for signage, slides and accessibility.

Convert pixels to physical size for a given DPI — for print layout, photo sizing and CSS.

Sitting and standing desk heights plus chair and monitor heights from your stature — BIFMA-based setup.

Seat height, depth and armrest height from your measurements — the chair setup most people never adjust.

Where the screen top should sit and how to tilt it from your seated eye height — the neck-saving geometry.

Keyboard tray height and the negative-tilt setup that keeps wrists neutral — RSI prevention geometry.

The riser-height and accessory plan that fixes the laptop's built-in ergonomic flaw, from your height.

A personalised alternation schedule for a sit-stand desk — the research ratio, not heroic all-day standing.

Schedule the eye-break rule across your workday and see how many breaks a session needs.

How much your blink rate drops at screens and the tear-film math behind computer dry-eye.

How your evening screen time may delay sleep — the melatonin-suppression context, stated honestly.

Your ideal book/screen reading distance from elbow-to-knuckle — the posture that eases focusing strain.

Convert eye-test scores between the US 20/x, metric 6/x and decimal/LogMAR systems.

WCAG contrast ratio between text and background colours — the accessibility pass/fail every designer needs.

Minimum readable body and large-text sizes across print, web and presentations — accessibility-grounded.

Where a reading sits on the ACC/AHA chart — with the home-vs-clinic and single-reading caveats stated.

Fasting, post-meal or random glucose against ADA reference bands — both mg/dL and mmol/L.

Total, LDL, HDL and triglycerides against reference bands — with the 'ratio and risk matter more' context.

Thyroid-stimulating-hormone result against reference bands — with the counter-intuitive direction explained.

Hb result against age- and sex-specific anaemia thresholds — the WHO cut-offs, with altitude and pregnancy notes.

Your 25(OH)D blood result against the deficiency/sufficiency bands — ng/mL and nmol/L, calmly framed.

Map an eGFR result to its KDIGO CKD stage — with the 'one number isn't a diagnosis' context.

Pulse-oximeter reading against standard bands — with the finger-temperature and nail-polish pitfalls.

Resting pulse against fitness and age context — the simplest health metric, neutrally framed.

Is a temperature normal, low or feverish? Bands by measurement site, with the modern-average update.

A quick BMI lookup with the WHO bands and the honest 'it's a screening tool, not a verdict' framing.

Estimate insulin resistance from fasting glucose and insulin — the research index, with its honest limits.

Normal heart rate, breathing rate and BP ranges by child age — for parents' reference, vet/doctor decides.

Your waist against WHO/IDF action points including the lower South-Asian thresholds — central-fat context.

The FIB-4 non-invasive liver-fibrosis index from routine bloods — a screening number, never a diagnosis.

Tally your modifiable and fixed heart-risk factors — a literacy tool that points you to a proper risk score.