Vertoq
Body Fat Calculator
Enter your measurements to estimate your body fat percentage.
Body fat vs BMI
BMI only compares your weight to your height. It can't tell whether that weight is muscle or fat. Body fat percentage measures body composition directly: how much of your weight is fat, and how much is lean mass such as muscle, bone, organs, and water. It answers a question BMI can only estimate.
The US Navy method
This calculator uses the US Navy circumference method, developed for military fitness assessments. It estimates body fat from a few tape-measure readings instead of specialized equipment.
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
Women's formula adds a hip measurement because fat distribution differs enough between men and women that neck and waist alone would underestimate it for most women.
Body fat categories (ACE)
These reference ranges come from the American Council on Exercise and differ by sex:
| Category | Men | Women |
|---|---|---|
| Essential fat | 2 – 5% | 10 – 13% |
| Athletes | 6 – 13% | 14 – 20% |
| Fitness | 14 – 17% | 21 – 24% |
| Average | 18 – 24% | 25 – 31% |
| Obese | Above 25% | Above 32% |
Limitations
Circumference-based methods like this one are estimates, not precise measurements. They're sensitive to measurement technique and can be thrown off by body shapes the formula wasn't tuned for. DEXA scans and skinfold calipers measure body fat more accurately, but they need equipment or trained hands this calculator can't replace. This method trades some precision for something anyone can do at home with a tape measure.
Frequently asked questions
How accurate is the US Navy method?
It's a reasonable estimate for most body types, typically within a few percentage points of more precise methods like DEXA. It tends to be less accurate for people with unusual body shapes or body fat levels at the extremes.
Where exactly should I measure?
Measure your neck just below the larynx, your waist at the narrowest point (or at the navel if there isn't one), and, for women, your hip at the widest point. Keep the tape snug but not compressing the skin.
Why is there an extra measurement for women?
The formula accounts for how fat distribution differs between men and women. Adding hip measurement corrects for a pattern that neck and waist alone would underestimate for most women.