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Body Fat Calculator
Body fat % from a tape measure.
The US Navy method uses circumferences (neck, waist, hip) instead of skinfolds — gets within ±3% of DEXA for most people, no special equipment needed. We show your number with the ACE category lookup.
Determines which formula and which categories apply
Below the larynx, perpendicular to the long axis of the neck
At the navel
Enter your numbers — gender, height, neck, waist (and hip for women) — then tap Calculate body fat for an estimate using the US Navy circumference method.
Body fat percentage chart (men and women)
Unlike BMI, body-fat percentage cut-offs differ for men and women, because women carry more "essential" fat for hormonal function. The American Council on Exercise (ACE) chart is the most commonly cited reference:
| Category | Men | Women |
|---|---|---|
| Essential fat | 2 – 5 % | 10 – 13 % |
| Athlete | 6 – 13 % | 14 – 20 % |
| Fit | 14 – 17 % | 21 – 24 % |
| Acceptable | 18 – 24 % | 25 – 31 % |
| Obese | 25 % + | 32 % + |
Don't try to live in the 'athlete' band
How the US Navy method works
The formula was developed by the US Navy in the 1980s as a field-deployable alternative to skinfold callipers. It estimates body-fat percentage from circumferences alone, which makes it cheap and repeatable.
Men
495 ÷ (1.0324 − 0.19077·log10(waist − neck) + 0.15456·log10(height)) − 450
All measurements in centimetres.
Women
495 ÷ (1.29579 − 0.35004·log10(waist + hip − neck) + 0.22100·log10(height)) − 450
The hip measurement is added for women because women store proportionally more fat in the gluteo-femoral region.
Why body-fat % beats BMI for tracking progress
BMI moves whenever your weight does — which means it falls when you lose muscle, and that's the wrong kind of weight loss. Body-fat percentage stays honest:
The same scale weight, two very different bodies
Two 80 kg men, both 1.78 m tall, both BMI 25.2:
- Person A — 12% body fat. Muscular, healthy, low metabolic risk.
- Person B — 28% body fat. Carrying ~15 kg more fat and ~15 kg less muscle. High metabolic risk.
Track both if you can. BMI gives a fast population-level check, body-fat % tells you whether your scale loss is fat or muscle. If your BMI is dropping but your body-fat % is staying put, you're losing muscle — eat more protein and lift more, cut less aggressively.
Other body-fat measurement methods compared
| Method | Accuracy | Cost | Best for |
|---|---|---|---|
| DEXA scan | ±1 % | ₹3,000 – 8,000 | Definitive baseline once or twice a year |
| Hydrostatic weighing | ±2 % | Lab access only | Research / very lean athletes |
| Bioelectrical scale | ±5–8 % | ₹3,000 – 15,000 | Casual home tracking; sensitive to hydration |
| Skinfold callipers | ±3–5 % | ₹500 + skill | Old-school; depends on tester |
| Navy circumference | ±3 % | Free | Repeatable, no equipment, this calculator |
For most people, the Navy method is the right balance: free, quick, and accurate enough to detect real change month to month. If you have access to a DEXA scan, use that as a calibration baseline once a year and the Navy method monthly.
Body fat calculator — frequently asked questions
How accurate is the US Navy body-fat formula?
Validation studies put the Navy circumference method within ±3% of DEXA scans for most people — close enough to track changes month-to-month. Hydrostatic weighing and DEXA are more accurate but cost ₹3,000–8,000 per scan, so for a free tape-measure check this is the best home option.
What's a healthy body-fat percentage?
Per the American Council on Exercise (ACE): men — 6–13% (athlete), 14–17% (fit), 18–24% (acceptable), 25%+ (obese). Women — 14–20% (athlete), 21–24% (fit), 25–31% (acceptable), 32%+ (obese). Women run higher because of essential fat needed for hormonal function.
Why is body-fat % better than BMI for athletes?
BMI can't tell muscle from fat. A 90 kg lifter at 12% body fat will show up as "overweight" on BMI, while a 90 kg sedentary person at 30% will land in the same category — yet their health risk is wildly different. Body-fat percentage looks past total weight at what that weight is made of.
How do I measure waist, neck and hip correctly?
Waist: at navel level, relaxed, exhale and measure. Don't suck in. Neck: just below the larynx (Adam's apple), sloping slightly downward. Hip (women only): the widest point around the hips and bum, feet together. Use a soft tape, snug but not pressing the skin in.
Do I need to measure hip if I'm a man?
No. The Navy formula for men uses only height, neck, and waist. The hip measurement is added for women because women carry a larger share of fat at the hip, which the equation needs to estimate accurately.
How often should I re-measure?
Once every 2–4 weeks is plenty. Body fat changes slowly — measuring daily or weekly creates noise. Take measurements at the same time of day (mornings, after the loo, before food / water), to keep conditions consistent.
Is the Navy method accurate for very lean or very obese people?
Less so. The formula was calibrated on a large but mostly average-bodied military population. For competitive bodybuilders below 8% (men) / 16% (women), DEXA is much better. At very high body fat (BMI 40+), the relationship between circumferences and total fat starts to drift, so treat the number as a ballpark.
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