Body Fat Calculator
Quick answer
Measure your height, neck, waist (and hips for women) in centimetres or inches and this calculator estimates your body fat percentage using the U.S. Navy circumference method — plus your fat mass and lean mass.
Last updated:
Your details
Everything runs in your browser — nothing is stored or sent anywhere.
U.S. Navy formula
Men: BF% = 495 ÷ (1.0324 − 0.19077·log10(waist − neck) + 0.15456·log10(height)) − 450
Women: BF% = 495 ÷ (1.29579 − 0.35004·log10(waist + hip − neck) + 0.22100·log10(height)) − 450
All measurements in centimetres. log10 is the base-10 logarithm.
Worked example
- 1
A woman: height 165 cm, neck 32 cm, waist 76 cm, hip 96 cm.
- 2
Waist + hip − neck = 76 + 96 − 32 = 140.
- 3
BF% = 495 ÷ (1.29579 − 0.35004·log10(140) + 0.221·log10(165)) − 450.
- 4
Result ≈ 28.4% — inside the “average” fitness category for women.
Interpreting your body fat %
| Your result | Category | What it means |
|---|---|---|
| Women 10–13% · Men 2–5% | Essential fat | The minimum needed for health. Going below it disrupts hormones and reproduction. |
| Women 14–20% · Men 6–13% | Athletes | Typical of competitive athletes. The lower end approaches the functional minimum. |
| Women 21–24% · Men 14–17% | Fitness | Lean yet healthy — common in people who exercise regularly. |
| Women 25–31% · Men 18–24% | Average | Normal for many healthy adults. Some notice more energy at the lower end. |
| Women 32%+ · Men 25%+ | Obese | Above the healthy range. Steady nutrition changes, strength training and daily movement are the priorities. |
American Council on Exercise (ACE) reference ranges for adults.
Frequently asked questions
Sources & further reading
Related calculators
BMI Calculator
Body Mass Index with healthy weight range and daily calories.
Open calculatorWaist-to-Hip Ratio Calculator
Abdominal obesity risk from the WHO 2008 waist-to-hip cut-offs.
Open calculatorIdeal Weight Calculator
Your healthy weight range from four medical formulas.
Open calculatorMacro Calculator
Daily protein, carb and fat grams for your goal.
Open calculatorThis calculator provides general estimates for informational purposes only and is not medical advice. For personal guidance, consult a qualified healthcare provider.