Estimate body-fat % from a tape measure — the U.S. Navy method, in metric or imperial.
Uses the U.S. Navy tape-measure formula. Typical accuracy is ±3–4 percentage points vs. lab methods. Take all measurements first thing in the morning, before food.
Estimate your body-fat percentage using the U.S. Navy tape-measure method (height, neck, waist, and hip for women). See your category (essential, athlete, fitness, average, obese) plus lean and fat mass in kg or lb.
The U.S. Navy circumference (tape) method, the most accessible body-fat estimate that needs no calipers or scanners. Men: 86.010·log10(waist − neck) − 70.041·log10(height) + 36.76. Women: 163.205·log10(waist + hip − neck) − 97.684·log10(height) − 78.387 (all measurements in inches).
Typical error vs. DEXA / hydrostatic weighing is ±3–4 percentage points for most people. Accuracy drops at the extremes (very lean athletes or very high body fat) and depends heavily on consistent tape placement.
WHO/ACE-style ranges — men: athletes 6–13%, fitness 14–17%, average 18–24%, obese 25%+. Women: athletes 14–20%, fitness 21–24%, average 25–31%, obese 32%+. Below the 'essential' floor (3% men / 12% women) is considered unhealthy.
Women carry more essential fat in the hip/thigh area, which the male formula ignores. Including hip circumference makes the female equation significantly more accurate.
Measure first thing in the morning, before eating. Stand relaxed, breathe out normally, keep the tape level and snug without compressing the skin. Repeat each measurement twice and average it.
Find your Body Mass Index in seconds — with the healthy weight range for your height.
Compare four classic ideal-weight formulas alongside the WHO healthy BMI range.
Find your Basal Metabolic Rate and daily calorie targets to maintain, lose or gain weight.