GWN Tools · Health

Body Fat Calculator

Estimate your body fat percentage with the US Navy tape method. Enter your height, neck and waist (plus hip for women). Switch between metric and imperial units.

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estimated body fat (US Navy method)

Informational only — not medical advice. Measure waist (and hip) loosely around the widest point; consult a professional for assessment.

About the body fat calculator

What is a body fat calculator? A body fat calculator estimates the percentage of your body weight that is fat, using tape measurements and the US Navy circumference formula.

How does the US Navy body fat method work?

The US Navy method estimates body fat from tape measurements. For men it uses height, neck and waist. For women it uses height, neck, waist and hip. Men: %fat = 495 ÷ (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450. Women: %fat = 495 ÷ (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height)) − 450, with all measurements in the same unit.

What are healthy body fat percentage ranges?

For men, a common guide is essential fat 2 to 5 percent, athletes 6 to 13 percent, fitness 14 to 17 percent, average 18 to 24 percent, and obese 25 percent or higher. For women the ranges are higher: essential 10 to 13 percent, athletes 14 to 20 percent, fitness 21 to 24 percent, average 25 to 31 percent, and obese 32 percent or higher.

How accurate is the tape-measure body fat method?

The US Navy method is a quick estimate, not a precise measurement. Accuracy depends on careful, consistent taping. Methods like DEXA scans are more accurate. Treat the result as informational only and consult a healthcare professional for assessment.