BMI → Body Fat Estimator (Deurenberg)
Converts BMI, age and sex into a body-fat estimate via the Deurenberg regression — with its limits stated plainly.
Deurenberg's regression explains why the same BMI means different fatness for a 25-year-old man and a 60-year-old woman — the age and sex terms shift the estimate by over 10 points. Standard error is about ±4%, and it inherits every limitation of BMI, so treat it as a ballpark only.
Formula
For general information only — not medical advice, a diagnosis or a treatment plan. Consult a qualified healthcare professional before making health, diet, medication or exercise decisions.
Converts BMI, age and sex into a body-fat estimate via the Deurenberg regression — with its limits stated plainly. The BMI → Body Fat Estimator (Deurenberg) is a free, private bmi to body fat tool — every result computes instantly in your browser with no sign-up and no data upload.
About BMI → Body Fat Estimator (Deurenberg)
Deurenberg's regression explains why the same BMI means different fatness for a 25-year-old man and a 60-year-old woman — the age and sex terms shift the estimate by over 10 points. It applies BF% = 1.2×BMI + 0.23×age − 10.8×sex − 5.4 (sex: M=1, F=0). Use the BMI → Body Fat Estimator (Deurenberg) to get an instant, clearly-explained result with the working shown step by step — free, private and with the source method cited.
How to use BMI → Body Fat Estimator (Deurenberg)
- 1Enter your details in the BMI → Body Fat Estimator (Deurenberg) input fields above.
- 2The result updates instantly with the working and reference bands shown.
- 3Adjust any value to explore how it changes the outcome — it's free and unlimited.
Why use BMI → Body Fat Estimator (Deurenberg)?
- ✓Instant bmi to body fat result that recomputes as you type — no waiting, no page reloads
- ✓100% client-side: your health data never leaves your browser
- ✓Shows the actual formula and your numbers substituted in, so you can see exactly how the result is reached
- ✓Based on published, citable sources (Deurenberg P et al., Br J Nutr 1991;65:105-14)
- ✓Free forever with no sign-up, account or app install
Frequently asked questions
How does the BMI → Body Fat Estimator (Deurenberg) work?+
Deurenberg's regression explains why the same BMI means different fatness for a 25-year-old man and a 60-year-old woman — the age and sex terms shift the estimate by over 10 points. The calculation uses the formula: BF% = 1.2×BMI + 0.23×age − 10.8×sex − 5.4 (sex: M=1, F=0). Everything runs instantly in your browser as you type — your inputs are never uploaded.
Is the BMI → Body Fat Estimator (Deurenberg) accurate, and what is it based on?+
The method is traceable to authoritative sources: Deurenberg P et al., Br J Nutr 1991;65:105-14. Results are estimates — individual variation always applies, so treat the output as a well-grounded starting point.
Is the BMI → Body Fat Estimator (Deurenberg) free and private?+
Yes. It's completely free with no sign-up, and all computation happens locally in your browser, so none of your health data ever leaves your device.
Can I use this for medical decisions?+
This tool is for general information only and is not medical advice. Always consult a qualified healthcare professional before making health decisions.
What can I use the BMI → Body Fat Estimator (Deurenberg) for?+
It's commonly used for bmi to body fat, deurenberg formula, body fat from bmi. Converts BMI, age and sex into a body-fat estimate via the Deurenberg regression — with its limits stated plainly.
Related Health tools
Adult BMI Calculator (WHO)
Body-mass index for adults with the WHO reference bands shown neutrally, plus the substituted formula step by step.
● LiveBMI Calculator (lb & inches)
US-style BMI from pounds and inches using the ×703 conversion, with CDC adult reference ranges.
● LiveBMI Calculator for Women
BMI with reference context written for women — what the index can and cannot say about female body composition.
● Live