Body Fat Calculator
Estimate your body fat percentage from tape measurements using the US Navy method.
Enter your details below.
How to use
- Enter your height, waist, and neck measurements in centimetres.
- Women: also enter your hip measurement.
- Read your estimated body fat percentage.
About this tool
The US Navy method estimates body fat from circumferences — waist and neck for men, plus hip for women — combined with height in a logarithmic formula. It is a cheap, equipment-free estimate, not a scan, so expect a few percentage points of error. The result is general information only, not medical advice, and trends over time matter more than any single reading.
Frequently asked questions
How do I measure correctly?
Measure waist at the navel, neck below the Adam's apple, and hip at the widest point, with the tape snug but not tight, and do not hold your breath.
How accurate is the Navy method?
It is usually within a few percentage points of lab methods for average builds, but less reliable for very muscular or very lean people.