Health and fitness tools
Body Fat Calculator
Estimate body fat percentage from height, neck, and waist or hip measurements using the U.S. Navy formula locally in your browser.
Enter your sex and measurements using the same unit. The calculator uses the U.S. Navy body fat formula with your height, neck, and abdomen (men) or waist and hip (women). Measure your neck just below the larynx, your waist at the narrowest point (women) or abdomen at the navel (men), and your hip at the widest point (women). The calculation runs locally in your browser; your values are not uploaded or stored.
The U.S. Navy formula estimates body fat from circumference measurements and height. It is a general screening estimate and does not account for factors such as age, ethnicity, muscle mass, bone density, or pregnancy. Categories follow the American Council on Exercise (ACE) ranges. For a clinical body fat assessment, consult a qualified healthcare professional. This estimate is not medical advice.
Estimate your body fat with the U.S. Navy method.
Enter your sex, height, neck circumference, and abdomen (men) or waist and hip (women) to estimate body fat percentage using the U.S. Navy formula. The result includes a category based on American Council on Exercise ranges. This is a general screening estimate and not a clinical measurement or medical advice; your values are calculated locally and are not uploaded or stored.
Frequently Asked Questions
Everything you need to know about this tool, how it works, and privacy.
How does the body fat calculator work?
Enter your sex, height, neck circumference, and abdomen (men) or waist and hip (women). The calculator applies the U.S. Navy body fat formula: for men, 86.010 x log10(abdomen - neck) - 70.041 x log10(height) + 36.76; for women, 163.205 x log10(waist + hip - neck) - 97.684 x log10(height) - 78.387. The result is a body fat percentage with a category based on American Council on Exercise ranges.
How should I take the measurements?
Measure your neck just below the larynx, your waist at the narrowest point (women) or abdomen at the navel (men), and your hip at the widest point (women). Use a soft tape measure snug against the skin without compressing it, and use the same unit for all measurements.
What do the body fat categories mean?
Categories follow the American Council on Exercise (ACE) ranges. For men: essential fat 2-5%, athletes 6-13%, fitness 14-17%, average 18-24%, obese 25% and above. For women: essential fat 10-13%, athletes 14-20%, fitness 21-24%, average 25-31%, obese 32% and above.
Is this a clinical measurement?
No. The U.S. Navy formula is a general screening estimate based on circumference measurements. It does not account for age, ethnicity, muscle mass, bone density, or pregnancy. For a clinical body fat assessment, consult a qualified healthcare professional. This estimate is not medical advice.
Do my measurements leave my browser?
No. The calculation and copy action run locally in your browser. CodeASystem does not upload or store the measurements you enter.