Free body fat calculator using the U.S. Navy method. Estimate your body fat percentage accurately with simple body measurements.
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Body fat percentage is often a better indicator of health than weight alone. Our calculator uses the U.S. Navy method—a proven technique that requires only a few simple measurements to estimate your body fat.
The Navy method uses measurements of your neck, waist, and hips (for women) along with height to estimate body fat percentage. While not as accurate as methods like DEXA scans, it's a reliable way to track changes over time without expensive equipment.
Navy Method (Men)
BF% = 86.010 × log₁₀(waist - neck) - 70.041 × log₁₀(height) + 36.76Only need a basic measuring tape.
Distinguishes between muscle and fat.
Measure real changes in body composition.
Track body composition changes during training.
Verify you're losing fat, not muscle.
Monitor an important health indicator.
Work toward specific body fat percentages.
For men: 10-20% is fitness range, 14-24% is healthy. For women: 18-28% is fitness range, 21-33% is healthy. Essential fat is 2-5% for men and 10-13% for women—below this is unhealthy.
Use a flexible tape measure. Measure your neck just below the larynx. Measure waist at the narrowest point (usually at navel level). For women, measure hips at the widest point. Keep the tape level and snug but not tight.
It has a margin of error of 3-4% compared to lab methods. It's more accurate than BMI and good enough for personal tracking.