Body Fat Percentage Calculator

It uses the U.S. Navy circumference method: enter height, neck and waist (men), plus hip for women, and it estimates body fat without calipers or a scan. When you also provide weight and age it adds the CUN-BAE estimate. This is a circumference method, not a skinfold-caliper method like Jackson-Pollock, so you only need a tape measure.

The Navy circumference method this tool uses is typically accurate to within about 3-5%, versus roughly 1-2% for a DEXA scan (the gold standard, which needs equipment). Skinfold calipers in trained hands are also about 3-5%, while home bioelectrical-impedance scales are the least reliable at about 5-8% and vary with hydration.

DEXA scan: ±1-2% (gold standard, requires equipment). Hydrostatic weighing: ±2-3%. BodPod (air displacement): ±2-3%. Skinfold calipers (trained user): ±3-5%. Bioelectrical impedance (home scales): ±5-8%, highly variable with hydration. This calculator uses the Navy Method (circumference-based), typically ±3-5%.

For men: essential fat 2-5%, athletic 6-13%, fitness 14-17%, average 18-24%, obese 25%+. For women: essential fat 10-13%, athletic 14-20%, fitness 21-24%, average 25-31%, obese 32%+. Women require higher essential fat due to hormonal and reproductive function.

Exercise alone rarely produces large fat loss without a calorie deficit. Cardio burns 200-400 calories per session — easily offset by diet. Resistance training adds muscle but may not reduce fat significantly without dietary control. Fat loss requires a sustained calorie deficit regardless of exercise type.

Sustainable fat loss is 0.5-1% of body weight per week. A 180 lb person can lose roughly 1-1.5 lb per week on a 500-750 calorie deficit. Faster loss accelerates muscle loss. Body fat percentage dropping 1-2 points per month is excellent progress; 3+ months is needed for visible changes.