Navlog Leg Calculator (Heading, GS, Time, Fuel)
One navlog row, fully computed: wind triangle plus variation, leg time and fuel — the four columns of paper planning in a single pass.
This is one row of the classic paper navlog: course → heading via the triangle, true → magnetic via variation, then time and fuel from ground speed. Fill a row per leg and the flight plan writes itself.
Formula
⚠️ For flight planning and education only — verify with official sources and certified equipment. Not for primary navigation.
One navlog row, fully computed: wind triangle plus variation, leg time and fuel — the four columns of paper planning in a single pass.
About Navlog Leg Calculator (Heading, GS, Time, Fuel)
Every paper navlog row asks the same four questions — what heading, what ground speed, how long, how much fuel — and student pilots answer them with three tools and two transcription errors. This calculator is the complete row: the exact wind triangle, the variation applied with the correct sign, leg time from the resulting ground speed, and fuel from the time. Plan a route by running it once per leg.
How to use Navlog Leg Calculator (Heading, GS, Time, Fuel)
- 1Enter — sensible defaults are pre-filled so you see a worked result immediately.
- 2Read the live results: .
- 3Check the "With your numbers" line to see the formula TH = TC + WCA; MH = TH + var(W)/− var(E); time = dist/GS; fuel = time × flow substituted step by step.
- 4Adjust inputs (or flip the unit toggle) until the scenario matches yours, then copy or share the result.
Why use Navlog Leg Calculator (Heading, GS, Time, Fuel)?
- ✓Instant, free and private — every calculation runs in your browser, nothing is uploaded
- ✓Built on the published formula TH = TC + WCA; MH = TH + var(W)/− var(E); time = dist/GS; fuel = time × flow with sources cited on the page
- ✓This is one row of the classic paper navlog: course → heading via the triangle, true → magnetic via variation, then time and fuel from ground speed. Fill a row per leg and the flight plan writes itself.
- ✓Switch units, tweak any input and watch every result update live
Frequently asked questions
What does 'east is least, west is best' actually mean here?+
Variation converts true to magnetic: where the magnetic pole sits west of true north (east variation), magnetic headings are numerically smaller — subtract east variation; add west. The tool's sign convention (W positive) implements the rhyme. Get it backwards and every heading is wrong by double the variation — 16° in this default's airspace.
Why compute the triangle before applying variation, not after?+
Because the wind triangle lives in true: chart courses are measured true and winds-aloft are reported true, so mixing magnetic values into the triangle corrupts the geometry by the variation. The chain is strict — TC + WCA = TH, then TH ± var = MH, then MH ± deviation = CH. Each conversion exactly once, in that order.
Is paper navlog planning obsolete with EFBs?+
The EFB automates exactly this arithmetic — which is why examiners still test it: the pilot who can run a leg by hand recognizes when the EFB was fed a wrong wind or TAS, and survives the tablet overheating on a glareshield in July. Ten minutes with this tool before a checkride rebuilds the skill the magenta line atrophies.
Which checkpoints make good leg boundaries?+
Features you cannot misidentify at 100 knots: river-highway crossings, towns with distinctive shapes, towers (charted AND tall), lake edges. Space them 10–20 nm — close enough to catch drift early, far enough that timing is meaningful. The first checkpoint matters most: it calibrates the actual wind while the fuel and options are still maximal.
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