Body Fat Calculator
The scale can't tell fat from muscle. Estimate your body fat percentage two ways: from a few tape-measure readings (the US Navy method) and from your BMI and age (the Deurenberg formula).
US Navy method
% body fat
≈ kg fat
Hodgdon & Beckett 1984 · tape measure
BMI method
% body fat
≈ kg fat
Deurenberg 1991 · BMI
Two different methods, shown separately. Categories: American Council on Exercise (ACE) body fat chart.
Your results are attached to the form below
These figures are estimates for general awareness only and are not medical advice or a diagnosis. Read our Medical Disclaimer.
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How this is calculated
US Navy method (Hodgdon & Beckett, 1984, as published in US Department of Defense Instruction 1308.3): men — 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76; women — 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387, with all measurements in inches (converted from your centimetres). BMI method (Deurenberg et al., 1991): body fat % = 1.20 × BMI + 0.23 × age − 10.8 × sex − 5.4, where sex is 1 for men and 0 for women. Categories follow the American Council on Exercise (ACE) body fat chart.
How to measure
- Neck — just below the Adam's apple, with the tape sloping neither up nor down.
- Waist (men) — around the belly button, after breathing out normally.
- Waist (women) — at the narrowest point, usually about halfway between the belly button and the bottom of the breastbone.
- Hip (women) — around the widest part of the buttocks.
Measure against bare skin, keep the tape level, and take each measurement two or three times.
Which result should I trust?
Both are estimates. The US Navy method uses your actual body shape, so it usually tracks changes better as you lose fat. The BMI method only knows your height, weight, age and sex, and was developed in a Dutch population — later research found that many Asian populations, including Indians, carry more body fat at the same BMI, so it may read low for you. For a precise measurement, a clinical method such as a DEXA scan is more accurate than either.
What the categories mean
Some body fat is essential for hormones and organ protection, which is why women naturally carry more than men. A result in the "obese" band is a reason to look at your diet and activity — and a good point to get personalised advice.