Body Fat Calculator
Estimate body fat percentage, fat mass and lean mass from tape measurements.
Body Fat Calculator
Estimate body fat percentage, fat mass and lean mass from tape measurements.
Starts in your browser. Instructions are below.
How to use Body Fat Calculator
- 01Choose metric or imperial units, and your sex.
- 02Enter your height, weight, neck and waist, plus hip if female.
- 03Measure each with a tape held snug but not tight, then read your body fat percentage, fat mass, lean mass and category.
About Body Fat Calculator
This body fat calculator uses the US Navy circumference method, which estimates body fat from neck, waist and (for women) hip measurements rather than skinfolds or a scan. It works because fat distributes fairly predictably relative to frame size, and it is accurate to roughly 3 to 4 percentage points for most people, good enough to track change over time.
Body fat percentage tells you more than BMI, which cannot tell muscle from fat. Typical healthy ranges run from about 8-19% for men and 21-32% for women, with essential fat around 3% and 12% respectively. Measure at the same time of day and in the same posture each time, and watch the trend rather than any single reading.
Frequently asked questions
- How accurate is the Navy method?
- It is usually within 3 to 4 percentage points of a DEXA scan, which is accurate enough for tracking progress over time.
- Where exactly do I measure?
- Measure your neck just below the larynx, your waist at the navel for men or at the narrowest point for women, and hips at the widest point if you're female.
- Why does it ask for different measurements by sex?
- Men and women store fat differently, so the formula for women includes hip circumference to stay accurate.
- Can I switch between metric and imperial units?
- Yes, use the Metric or Imperial toggle at the top and the measurement fields switch to cm or inches and kg or lb.
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