Body fat calculator
Body fat percentage from a few tape-measure readings.
Body fat
Rounded for displayBody fat: ≈ 17.0%
- ACE category
- Fitness
- Fat mass
- ≈ 11.9 kg
- Lean mass
- ≈ 58.1 kg
- Essential: 0 – 6
- Athletes: 6 – 14
- Fitness: 14 – 18
- Average: 18 – 25
- Obese: 25 – 50
How it works
The US Navy method (Hodgdon and Beckett, 1984) estimates body fat from circumferences and height. Measurements are converted to inches and put into the published equations, which use base-10 logarithms.
Categories follow the American Council on Exercise chart. Men: essential fat 2–5%, athletes 6–13%, fitness 14–17%, average 18–24%, obese 25% and over. Women: 10–13%, 14–20%, 21–24%, 25–31%, 32% and over.
Tape-measure methods are typically within a few percentage points of lab methods, and depend on careful measuring. This is a general estimate, not medical advice. For personal guidance, speak to a doctor or registered dietitian.
Formula
Men: %BF = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76 Women: %BF = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387 (all measurements in inches)
Worked example
A man 175 cm tall (68.9 in) with a 38 cm neck and an 85 cm waist (14.96 in and 33.46 in) has an estimated 17.0% body fat, in the fitness range. At 70 kg that is about 11.9 kg of fat and 58.1 kg of lean mass.
Questions people ask
Where do I measure?
Neck just below the larynx; waist at the navel for men and at the narrowest point for women; hips at the widest point. Keep the tape level and snug without pressing in.
How accurate is the US Navy method?
It is an estimate, typically within a few percentage points of laboratory methods, and less accurate for very lean or very muscular people.