Body Fat Calculator
Estimate your body fat percentage using the US Navy circumference method. More accurate than BMI for fitness tracking — enter your measurements for an instant estimate.
Part of our Health Calculators collection.
Body Fat Calculator
Free online calculator
Convert: 5'10" = 70 inches
Measure at navel level
Measure just below the larynx
Measure at widest point
How to Use This Calculator
- 1
Select your sex.
- 2
Enter your height, waist circumference (at navel level), and neck circumference (just below the larynx).
- 3
Women: also enter hip circumference at the widest point.
- 4
See your estimated body fat percentage and fitness category.
US Navy Body Fat Formula
Male: % Body Fat = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76 Female: % Body Fat = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387 All measurements in inches. This method is accurate within 3–4% for most adults. Categories (men): Essential <6%, Athletic 6–13%, Fit 14–17%, Average 18–24%, Obese 25%+ Categories (women): Essential <14%, Athletic 14–20%, Fit 21–24%, Average 25–31%, Obese 32%+
Example Calculation
Example: 5'10" male, 33" waist, 15" neck
Inputs
sex: maleunits: imperialheight: 70waist: 33neck: 15hip: 38
Result
~17% body fat — Fit range
17% body fat for a man falls in the 'Fit' category (14–17%). Athletic is under 14%, average is 18–24%.
Frequently Asked Questions
How accurate is the Navy method?
Typically within 3–4% of DEXA scan results for average adults. It's less accurate for very lean or very obese individuals. DEXA scans are the gold standard but expensive — this method is a reliable free alternative.
Why is body fat better than BMI?
BMI doesn't distinguish muscle from fat. A muscular athlete and an overweight sedentary person can have the same BMI. Body fat percentage directly measures the proportion of fat, making it a better measure of body composition and fitness.
How do I reduce body fat?
A combination of caloric deficit (use the Calorie/TDEE calculator) and resistance training is most effective. Cardio alone is less effective for fat loss than combining it with weight training.