Body Fat Calculator
Estimate your body fat percentage with a tape measure, using the US Navy method
Measure just below the larynx, with the tape sloping slightly downward toward the front.
Measure at the navel. Measure to the nearest 0.5 cm.
16.9%
Body fat percentage
Fitness
ACE category
12.7 kg
Fat mass
62.3 kg
Lean mass
ACE body fat categories — men
| Category | Range |
|---|---|
| Essential fat | 2-5% |
| Athletes | 6-13% |
| Fitness | 14-17% |
| Average | 18-24% |
| Obese | 25%+ |
The US Navy method is typically within about 3-4% of a DEXA scan. It tends to overestimate body fat for very lean or very muscular people, and underestimate it for people who carry fat outside the measured areas. Treat this as an estimate, not a diagnosis.
Instant Results
Body fat, fat mass, and lean mass update live as you type
Metric or Imperial
Enter measurements in whichever units you use
Guarded Maths
Impossible measurements show a friendly message instead of a broken result
Frequently asked questions
How accurate is the US Navy body fat method?
It is typically within about 3-4% of a DEXA scan for most people. It tends to overestimate body fat in very lean or very muscular people, and underestimate it for people who carry fat outside the measured areas.
Where exactly do I measure my neck and waist?
Measure the neck just below the larynx (Adam's apple), with the tape sloping slightly downward toward the front. Measure the waist at the navel for men, or at the narrowest point of the torso for women. Keep the tape snug but not compressing the skin.
Why do women need a hip measurement but men do not?
The Navy formula uses different regression equations for each sex. The women's formula includes hip circumference because fat distribution patterns differ enough between sexes that the men's waist-only formula is not accurate for women.
What does "check your measurements" mean when I see it?
The formula takes the log of (waist minus neck) for men, or (waist plus hip minus neck) for women. If that value is zero or negative — usually from a measurement typo or unit mix-up — the maths breaks down, so the calculator shows this message instead of a nonsense result.