Body Fat Percentage Calculator
Estimate your body fat percentage using the US Navy circumference method. Measure your height, neck, waist, and hips (women only) with a tape measure.
Reference ranges (male)
What is the US Navy body fat method?
The US Navy circumference method estimates body fat percentage from body measurements rather than underwater weighing or DEXA scanning. It was developed for use in the US military fitness assessment program and is widely used because it requires only a tape measure.
For men, the formula uses neck and waist circumference along with height. For women, hip circumference is added because fat distribution differs between sexes. The method is validated with an accuracy of ±3–4% body fat for most people.
How to measure correctly
- Neck — measure below the larynx (Adam's apple), keep the tape perpendicular to the neck
- Waist (men) — measure at the navel (belly button level)
- Waist (women) — measure at the narrowest point, usually just above the navel
- Hips (women) — measure at the widest point around the buttocks
Take measurements in the morning before eating. Stand upright, breathe out naturally, and ensure the tape is snug but not compressing the skin.
Frequently asked questions
How accurate is the Navy method?
Studies show the Navy method is accurate to within 3–4% body fat for most adults. It tends to slightly overestimate body fat in very lean individuals and underestimate it in people with a high fat-to-muscle ratio.
How is this different from BMI?
BMI (Body Mass Index) uses only height and weight, so it cannot distinguish muscle from fat. Body fat percentage is a more direct measure of body composition. A muscular person can have a high BMI but a low body fat percentage.
What is the athletic body fat range?
For men, athletic body fat is typically 6–13%. For women, 14–20%. These ranges are associated with high levels of fitness and low cardiovascular risk, but very low body fat (below essential fat levels) can impair hormone function and health.
Can I use this for tracking progress over time?
Yes. While any single measurement has error, tracking the trend over weeks or months using consistent measurement technique is a reliable way to monitor body composition changes during diet or training programmes.
