Fuel & Forge / Free tools / Body Fat Calculator
Body Fat Calculator
This estimates your body fat percentage with the US Navy method, using only a tape measure. It is usually within 3 to 4 percentage points of a DEXA scan, and good for tracking change over time.
Fill in the fields to see your result.
How it's calculated
The US Navy method uses the difference between your waist and neck (plus hips for women) relative to your height. More fat around the middle raises the estimate.
Men: 495 ÷ (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450.
Women: 495 ÷ (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height)) − 450. All measurements in centimetres.
Questions
How accurate is the US Navy body fat method?
Usually within 3 to 4 percentage points of a DEXA scan for most people. It is less accurate for very lean or very muscular people, but it is consistent, which makes it good for tracking change.
Where exactly do I measure my waist?
Around your navel for men, and at the narrowest point for women, relaxed and after breathing out. Keep the tape level all the way round.
What is a healthy body fat percentage?
Roughly 10 to 20% for men and 18 to 28% for women is a healthy range for most adults. Athletes are often lower.
Let a coach do this every week
A calculator gives you a starting point. Fuel & Forge sets your calories, macros and training, then adjusts them every week from your check-ins, so you never have to recalculate.
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