How to measure your body fat with a tape
- Use a soft tape measure, standing relaxed and breathing out normally. Do not pull the tape tight.
- Measure your height, your neck just below the larynx, and your waist (men: at the navel; women: at the narrowest point). Women also measure the hips at their widest.
- Enter the numbers in centimetres or inches. Add your weight to see fat mass and lean mass.
- Measure two or three times and use the average; repeat monthly at the same time of day to track change.
The US Navy method
This calculator uses the circumference equations developed for the US Navy by Hodgdon and Beckett. They estimate body density from height and the neck, waist and (for women) hip measurements, then convert it to a body fat percentage. Because fat around the waist grows while the neck changes little, the difference between them tracks body fat surprisingly well. Compared with DEXA scans and underwater weighing, the method is usually within 3–4 percentage points for most people, which is similar to bathroom scales with bioimpedance and much cheaper than lab tests.
The categories follow the American Council on Exercise chart. Essential fat is the minimum the body needs; women naturally carry more. Very muscular people with thick necks may get readings that are too low, and people who carry fat mainly on the hips or thighs may get readings that are off.
Everything is calculated in your browser; your measurements are not sent anywhere.
Is body fat percentage better than BMI?
It says more about body composition, because BMI cannot tell muscle from fat. Both are rough screening tools.
What is a healthy body fat percentage?
Roughly 10–20% for men and 18–30% for women, depending on age. Higher values raise health risks over time.
Why does my result change from day to day?
Small differences in where and how tight you measure have a big effect. Measure the same way each time and compare monthly trends.