Body fat calculator
Measure your neck and waist with a tape. Women add hips. You get your body fat percentage in about two minutes, using the same method the US Navy uses for its fitness tests.
How to measure
- Neck: just below the Adam's apple. Keep the tape level and flat on the skin.
- Waist: men at the belly button, women at the narrowest point. Relax your stomach. Do not pull it in.
- Hips (women): at the widest point of the buttocks.
- Height: no shoes, standing straight.
Measure in the morning, before you eat. Take each measurement twice and use the average.
Your measurements
What this number means
Body fat percentage is the share of your weight that is fat. A 200 lb man at 20% carries 40 lb of fat and 160 lb of everything else: muscle, bone, water and organs.
It tells you more than the scale does. Two people can weigh the same and look nothing alike. When you lift weights and eat enough protein, your weight can stay flat while your body fat drops. The scale calls that no progress. Your body fat number calls it a win.
See where you sit on the body fat chart by age and sex.
How accurate is it?
The Navy tape method is an estimate. On most people it lands within a few points of a DEXA scan. It misses more on very lean athletes and on people who carry most of their weight in one area.
That's fine for tracking. What matters is that you measure the same way every time. If your number drops from 24% to 21% over 10 weeks, that change is real even if the true starting number was 26%.
Want a tighter number? Read how the main measurement methods compare.
Tools that make tracking easier
- Body fat scalesSmart scales that log weight and a body fat estimate to your phone every morning.
- Calipers and tape measuresThe cheapest way to get consistent numbers. Most cost less than a takeout meal.
- Fitness trackers and smart ringsOura, Amazfit, Apple Watch and others. What they track and what they don't.
- Supplements worth your moneyThe short list with real research behind it. No fat burners.
Common questions
What is a healthy body fat percentage?
For most adults, 10% to 20% for men and 18% to 30% for women is a healthy range. The exact range shifts with age. The chart page breaks it down.
Why is my smart scale number different from this calculator?
They use different methods. Smart scales send a small current through your feet and guess from how fast it travels. Water changes that a lot. Neither number is wrong. Pick one and stick with it.
How often should I measure?
Once a week, same day, same time, same conditions. Daily numbers bounce around with water and food. Weekly numbers show the trend.
Can I lose fat and gain muscle at the same time?
Yes, especially if you're new to lifting or coming back after time off. That's why body fat percentage is a better scorecard than weight.