Body Fat Calculator
Estimate your body fat percentage using the U.S. Navy circumference method.
Inputs
Only used for female calculation.
Body Fat
16.9%
Category
Average
Step by step
Circumference difference: waist − neck
85.0 − 38.0
= 47.00 cm
log₁₀ of (waist − neck)
log₁₀(47.00)
= 1.67210
log₁₀ of height
log₁₀(175.0)
= 2.24304
Compute denominator: 1.0324 − 0.19077 × log(waist−neck) + 0.15456 × log(h)
1.0324 − 0.19077 × 1.67210 + 0.15456 × 2.24304
= 1.06010
Body fat % = 495 ÷ denominator − 450
495 ÷ 1.06010 − 450
= 16.9%
ACE category
= Average
How it works
The U.S. Navy method estimates body fat from body circumference measurements and height using a validated formula. Measure snugly with a flexible tape for best accuracy.
Formulas
US Navy — Male
BF% = 495 ÷ (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450
- BF%
- Body fat percentage
- w
- Waist circumference (cm)
- n
- Neck circumference (cm)
- h
- Height (cm)
US Navy — Female
BF% = 495 ÷ (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.22100 × log₁₀(height)) − 450
- BF%
- Body fat percentage
- w
- Waist circumference (cm)
- p
- Hip circumference (cm)
- n
- Neck circumference (cm)
- h
- Height (cm)
Guides that use this calculator
This is an estimate and not medical advice. Body composition results vary with measurement technique and individual body shape. Consult a healthcare professional for clinical assessment.
Frequently Asked Questions
How accurate is this?
The Navy method is typically within ~3–4% of clinical methods for most people, though technique and body shape affect results. It's a convenient estimate, not a lab measurement.
Where do I measure?
Waist at the navel, neck just below the larynx, and (for women) hips at the widest point. Keep the tape level and snug but not compressing the skin.