How this body fat calculator works
This calculator uses the US Navy circumference method. You enter height, neck and waist (plus hip for women) and the formula estimates body fat from the logarithms of those measurements. It needs only a tape measure, which makes it far more accessible than skinfold callipers or a DEXA scan.
Accuracy is typically within about 3 to 4 percentage points of a DEXA scan for most people, which is good enough to track direction over time.
How to measure correctly
Small measuring errors change the result a lot, so be consistent:
- Neck: just below the larynx, tape sloping slightly down to the front.
- Waist (men): at the navel, relaxed, after a normal exhale.
- Waist (women): at the narrowest point of the torso; hip: at the widest point of the buttocks.
- Measure in the morning, before eating, and take each measurement twice.
Typical body fat ranges
Rough ranges from the American Council on Exercise: essential fat 2–5% (men) and 10–13% (women); athletes 6–13% and 14–20%; fitness 14–17% and 21–24%; average 18–24% and 25–31%. Higher than that is in the obese range. These are guides, not verdicts.
Frequently asked questions
How accurate is the Navy body fat formula?
It is an estimate. For most people it lands within roughly 3 to 4 percentage points of DEXA. It is best used to track change over weeks, not for a precise single number.
What is a good body fat percentage for men and women?
Roughly 14–24% for men and 21–31% for women falls in the fitness-to-average range. Women naturally carry more essential fat than men.
How often should I measure body fat?
Every 2 to 4 weeks is plenty. Daily changes are mostly noise from water and food.
Results are estimates for general information and are not medical advice. See our disclaimer. Talk to a doctor or registered dietitian before making major changes to your diet or training.