Body Fat Calculator
Estimate body fat percentage from height, neck and waist measurements (U.S. Navy method).
How it is calculated (U.S. Navy method)
The method estimates body fat from tape measurements, using logarithms of your measurements in centimeters:
- Men: 495 ÷ (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450
- Women: 495 ÷ (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height)) − 450
Fat mass is your weight × body fat %, and lean mass is the rest.
Worked examples
- Man, 178 cm tall, neck 38 cm, waist 85 cm, 80 kg: about 16.4% body fat, which is 13.1 kg of fat and 66.9 kg of lean mass.
- Woman, 165 cm tall, neck 32 cm, waist 75 cm, hip 98 cm: about 28.9%.
Common body fat ranges
| Range | Men | Women |
|---|---|---|
| Essential fat | 2 to 5% | 10 to 13% |
| Athletes | 6 to 13% | 14 to 20% |
| Fitness | 14 to 17% | 21 to 24% |
| Average | 18 to 24% | 25 to 31% |
| Higher range | 25% and above | 32% and above |
Frequently asked questions
How accurate is the Navy body fat method?
It is an estimate and can differ from methods such as DEXA scans by several percentage points. Measure carefully and use the same method over time to see changes.
How do I measure correctly?
Stand relaxed, keep the tape snug but not tight and level with the floor, and measure the neck, waist and hips (for women) without compressing the skin. Take each measurement twice.
Is this a diagnosis?
No. Body fat is only one piece of information about health. For concerns about your body composition, talk to a doctor.
Who should not use this calculator?
It is designed for healthy adults. It is not suitable for children, teenagers or during pregnancy.
This calculator is for general information only and is not medical advice.