The U.S. Navy formula is sensitive to a few centimeters or a fraction of an inch. Measure the same way each time if you want to compare progress over the next few weeks.
Free Fitness Tool
Body FatPercentage Calculator
Estimate your body fat percentage instantly with the U.S. Navy formula. Enter a few measurements to see your body fat category, fat mass, lean mass, and the best next step for your FitForge plan.
Real-time results, no submit button
Male and female formula support
Lean mass and fat mass breakdown
Neck, waist, and hip measurements should use the same unit as your height. Age is shown in your summary for context, but the Navy formula itself is driven by your body measurements.
Inputs
Build Your Estimate
Results update as you type. Use relaxed posture and a soft tape measure for the most consistent reading.
Gender
Height Unit
Weight Unit
Measurement guide
Measure your neck just below the larynx, your waist at the navel or narrowest point, and for females your hips at the widest point. Keep the tape level and snug, not tight.
Essential fat, athlete, fitness, average, and obese are broad population ranges. Use them as a planning reference, not as a full medical assessment.
- Cutting phase: use the estimate to set a fat-loss target.
- Recomp phase: track lean mass while weight changes slowly.
- Performance phase: keep training volume matched to your goal.