Body Fat Calculator
Estimate your body fat percentage from simple tape-measure measurements.
How body fat is estimated
This tool uses the U.S. Navy circumference method, developed by the U.S. Navy as a quick, tape-measure-only alternative to skinfold calipers or body scans. It uses your height along with neck and waist measurements for men, adding a hip measurement for women, in a formula based on logarithms of these circumferences.
Getting an accurate measurement
- Measure your neck just below the larynx (Adam's apple), and your waist at the navel while standing relaxed - don't suck in your stomach
- Women should measure hips at the widest point
- Use a flexible tape measure, keep it snug but not compressing the skin, and take each measurement two or three times to average out any error
Frequently asked questions
How accurate is the U.S. Navy method?
It's generally accurate within about 3-4% of body fat compared to more precise methods like DEXA scans, which makes it a solid free estimate for tracking progress over time, though not a substitute for clinical measurement.
Why does the formula need a hip measurement for women but not men?
Body fat distribution differs by sex - women typically store more fat around the hips, so the Navy method's female formula includes a hip measurement to account for this, while the male formula relies on waist and neck alone.
What do the body fat categories mean?
The ranges follow the American Council on Exercise classification: essential fat (the minimum needed for basic health), athletes, fitness, average, and obese - with different thresholds for men and women since healthy body fat levels differ by sex.