Estimate your body fat percentage using the US Navy formula — no calipers needed.
Measure at navel level
Measure just below the larynx
Measure at widest point
The Body Fat Calculator uses the US Navy circumference method to estimate your body fat percentage from simple tape measurements. Males need waist and neck circumference; females also need hip circumference. The formula was developed by the US Navy as a quick, equipment-free method that correlates well with hydrostatic weighing. Enter your measurements and weight to see body fat %, fat mass, and lean mass.
1. Select your gender.
2. Enter waist, neck (and hip for females), height, and weight.
3. Get body fat percentage, fat mass, and lean mass.
US Navy Formula:
Male: 495 / (1.0324 - 0.19077 x log10(waist - neck) + 0.15456 x log10(height)) - 450
Female: 495 / (1.29579 - 0.35004 x log10(waist + hip - neck) + 0.22100 x log10(height)) - 450
All measurements in cm.
Fat Mass = Weight x (Body Fat % / 100)
Lean Mass = Weight - Fat Mass
Example: Male, 80 kg, 175 cm height, 85 cm waist, 38 cm neck
log10(85 - 38) = log10(47) = 1.6721
log10(175) = 2.2430
Body fat = 495 / (1.0324 - 0.19077 x 1.6721 + 0.15456 x 2.2430) - 450
= 495 / (1.0324 - 0.3190 + 0.3466) - 450
= 495 / 1.0600 - 450 = 467.0 - 450 = 17.0%
Fat mass = 80 x 0.17 = 13.6 kg, Lean mass = 66.4 kg