Body Fat Calculator
Estimate your body fat percentage using the U.S. Navy method. Just enter a few measurements — no calipers or special equipment needed.
The U.S. Navy Method Explained
This calculator uses the U.S. Navy body fat formula, developed by Hodgdon and Beckett at the Naval Health Research Center. It estimates body fat from circumference measurements — waist, neck, and (for women) hip. Studies show it correlates reasonably well with DEXA scans, with a typical error margin of 3-4%.
The formula works by relating the log of specific body circumferences to height. Fat tends to accumulate around the waist, so a larger waist-to-neck ratio generally means higher body fat. It's not perfect — muscular individuals may get slightly inflated readings — but it's solid for a free, equipment-free estimate.
Why Body Fat Matters More Than Weight
Two people can weigh the same but have vastly different body compositions. A 180-pound person at 15% body fat looks and functions very differently from one at 30%. That's why body fat percentage is often a better health indicator than BMI alone. For the full picture, pair this with your BMI and ideal weight.
⚠️ Medical Disclaimer
This tool provides estimates for informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making health decisions. Results may vary based on individual factors not captured by this calculator.