Body Fat Calculator
Free body fat calculator with the US Navy method: your body fat percentage from height, neck, waist and hips, with fat mass, lean mass and the ACE category.
Measure with a soft tape, relaxed, without pulling it tight. Neck: just below the larynx. Waist: men at the navel, women at the narrowest point. Hips (women only): at the widest point.
Weight and age are optional: they add fat mass, lean mass and a second estimate from BMI.
Categories (American Council on Exercise)
| Category | Male | Female |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Obese | 25%+ | 32%+ |
What it does
The US Navy method estimates body fat from a few tape measurements and your height, with formulas published by the Naval Health Research Center in 1984. It needs no special equipment and usually lands within 3 to 4 percentage points of laboratory methods. Fat mass is your weight times the percentage; lean mass is the rest: muscle, bone, organs and water.
How to use it
- Choose metric or imperial units and your sex.
- Type your height and your neck and waist measurements; women also type the hips.
- Read your body fat percentage and its category. Add weight and age to see fat and lean mass.
The arithmetic runs in your browser. Nothing you type is sent anywhere and nothing is stored, so you can use these with real numbers.
Frequently asked questions
How accurate is the US Navy method?
For most people it comes within 3 to 4 percentage points of a DEXA scan. It is less accurate for very muscular people and for people with a lot of abdominal fat. Measuring the same way each time matters more than the absolute number.
What is a healthy body fat percentage?
By the American Council on Exercise ranges, about 14 to 24% for men and 21 to 31% for women is fitness to average. Essential fat, the minimum needed for health, is 2 to 5% for men and 10 to 13% for women.
Why is the BMI estimate different?
The BMI estimate (Deurenberg formula) only knows weight, height, age and sex, so it cannot tell muscle from fat. The tape measurements see where the fat is, which is why the Navy result is the main one.
Is this medical advice?
No. It is a general estimate for adults. For a diagnosis, or if you are pregnant or ill, talk to a doctor.
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