Body Fat Calculator
Estimate body fat % using the Navy tape method
cm
cm
cm
Body Fat Percentage
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Category
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Fat Mass
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Lean Mass
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What is body fat percentage?
Body fat percentage is the proportion of your total body weight that is fat tissue. Unlike BMI, it distinguishes between fat mass and lean mass (muscle, bone, water), making it a much more accurate measure of fitness and health. Two people with the same BMI can have very different body compositions.
Formula used
U.S. Navy Tape Method (used here — tape measure only):
Male:
BF% = 495 / (1.0324 − 0.19077×log10(waist−neck) + 0.15456×log10(height)) − 450
Female:
BF% = 495 / (1.29579 − 0.35004×log10(waist+hip−neck) + 0.22100×log10(height)) − 450
All measurements in centimetres.
Healthy ranges:
Men: 6–13% athletic, 14–17% fitness, 18–24% average
Women: 14–20% athletic, 21–24% fitness, 25–31% average
How to use this calculator
- Select metric (cm) or imperial (in)
- Select your sex — women need hip measurement too
- Measure height, neck (below Adam's apple), and waist (at navel)
- Women: also measure hips at widest point
- Click Calculate
Example
How to measure correctly:
- Neck: measure just below the larynx, head straight
- Waist: measure at the navel, standing relaxed (not sucked in)
- Hip (women only): measure at the widest point of buttocks
Example — Male, 175 cm, neck 38 cm, waist 85 cm:
BF% = 495 / (1.0324 − 0.19077×log10(47) + 0.15456×log10(175)) − 450
= 495 / (1.0324 − 0.319 + 0.347) − 450 = ~16.5% (Fitness range)
Body fat categories:
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletic | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Obese | 25%+ | 32%+ |
Frequently asked questions
Accuracy is within ±3–4% compared to DEXA scan results for most people. It is less accurate for very lean athletes or obese individuals but is reliable for general tracking.
For men: 10–20% is generally healthy. For women: 18–28%. Athletes often fall below these ranges. Above 25% (men) or 32% (women) is associated with increased metabolic health risks.
Every 4–6 weeks. Always measure at the same time of day (morning, before eating) for consistency. Daily fluctuations of 1–2% are normal due to hydration and food intake.