Body Fat Calculator
Estimate body fat percentage from tape measurements — the US Navy method.
Quick answer
- Formula: US Navy — Men: BF% = 495 / (1.0324 − 0.19077·log₁₀(waist − neck) + 0.15456·log₁₀(height)) − 450 · Women: BF% = 495 / (1.29579 − 0.35004·log₁₀(waist + hip − neck) + 0.221·log₁₀(height)) − 450 (all measurements in cm)
- Worked example — Body fat: 16.1% (full example below).
Body Fat Calculator
| Body fat | 16.1% |
| Fat mass | 12.9 kg |
| Lean mass | 67.1 kg |
A man of 80 kg and 180 cm with a 38 cm neck and 85 cm waist measures about 16.1% body fat — 12.9 kg of fat mass and 67.1 kg of lean mass.
The US Navy circumference method estimates body fat from height plus neck, waist (and hip, for women) measurements, using logarithmic equations developed for naval personnel screening. It needs only a tape measure and typically lands within about 3–4 percentage points of laboratory methods such as DEXA.
Measure the waist at the navel, the neck just below the Adam's apple, and hips at the widest point, keeping the tape snug but not compressing the skin. Results are estimates for general information, not medical advice.
The formula
Worked example
A man of 80 kg and 180 cm with a 38 cm neck and 85 cm waist measures about 16.1% body fat — 12.9 kg of fat mass and 67.1 kg of lean mass.
The example is pre-loaded in the result panel — press Calculate with your own numbers to replace it.
Frequently asked questions
How accurate is the Navy method?
Studies generally place it within roughly 3–4 percentage points of DEXA for most people. It is very good for tracking change over time with the same tape technique, even if the absolute figure is approximate.
What is a healthy body fat range?
Commonly cited ranges (American Council on Exercise): men 6–24% and women 16–30% span 'athletic' to 'acceptable'. Essential fat is about 2–5% for men and 10–13% for women.
Where exactly do I measure my waist?
Horizontally at the level of the navel, at the end of a normal exhale, without sucking in. Measuring at a different point each time is the biggest source of error.
Category: Health & Fitness calculators
Sources & methodology
This calculator applies the formula shown on this page exactly as written, using the standard definitions for its inputs. Results are computed from the values you enter — no data is stored — and are rounded only for display.
Content last reviewed by CalcHub Editorial.
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