Body Fat Calculator
Estimate your body fat percentage with a tape measure using the US Navy method, and see your fat mass and lean mass.
Body fat
19.2% average
- Fat mass
- 15 kg
- Lean mass
- 63 kg
About 19.2% of your weight is fat (15 kg), in the "average" range for men.
How it's worked out
- Waist minus neck
88 − 3850 cm - US Navy formula
495 ÷ (1.0324 − 0.19077 × log(waist − neck) + 0.15456 × log(height)) − 45019.2% - Fat mass
78 kg × 19.2%15 kg
- A tape-measure estimate, usually within 3 to 4 percentage points of a lab scan. Measure in the morning, tape level and snug.
The US Navy formula (metric)
Men: 495 ÷ (1.0324 − 0.19077 × log(waist − neck) + 0.15456 × log(height)) − 450
Worked example
A man 175 cm tall with an 88 cm waist and 38 cm neck: log(50) = 1.699 and log(175) = 2.243, giving 495 ÷ 1.0550 − 450 = 19.2% body fat, in the "average" range.
Questions people ask
How accurate is the US Navy method?
It usually lands within 3 to 4 percentage points of a lab scan, good enough to track changes over time with the same tape and technique.
Where do I measure?
Waist at the navel, neck just below the Adam's apple, and for women the hips at their widest. Keep the tape level and snug, not tight.
What is a healthy body fat?
On the American Council on Exercise scale, about 14% to 24% for men and 21% to 31% for women covers the fitness to average ranges.
About this calculator
Formula and rules last checked 25 October 2026Written and tested by the CalculatorDex teamReport a problem