Body Fat Calculator
Estimate body fat percentage with the US Navy circumference method using waist, neck, and height in centimeters.
- ACE "fitness" range (men)
- 14–17%
- ACE "average" range (men)
- 18–24%
Formula: BF% = 495 ÷ (1.0324 − 0.19077×log₁₀(waist−neck) + 0.15456×log₁₀(height)) − 450
About Body Fat Calculator
Body Fat Calculator is a free online calculator that gives you an instant, accurate result as you type. Estimate body fat percentage with the US Navy circumference method using waist, neck, and height in centimeters.
The calculation uses the standard formula BF% = 495 ÷ (1.0324 − 0.19077×log₁₀(waist−neck) + 0.15456×log₁₀(height)) − 450 and updates live with every change to the inputs. Everything runs client-side in your browser — fast, private, and free to use as often as you like.
This tool uses the US Navy formula for men; the women's version also requires a hip measurement, so results for women will differ.
Results are estimates for educational purposes and not medical advice.
Frequently Asked Questions
Is Body Fat Calculator free to use?
Yes. Body Fat Calculator is completely free, with no sign-up, no downloads, and no usage limits. You can use it as many times as you like on any device with a web browser.
How accurate is this calculator?
The calculator applies the standard formula (BF% = 495 ÷ (1.0324 − 0.19077×log₁₀(waist−neck) + 0.15456×log₁₀(height)) − 450) with full floating-point precision and rounds only the displayed result. For most practical purposes the results are exact.
How accurate is the US Navy body fat method?
Tape-measure methods are typically within 3–4 percentage points of DEXA scans for most people, making them a useful tracking tool rather than a clinical measurement.
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