inyourbrowser.com

Body fat calculator for men

Estimate your body fat percentage using the US Navy circumference method. For men, you need three measurements: neck, waist, and height. No calipers or scales are needed, just a measuring tape. All calculations run locally in your browser.

Sex

Units

Measure neck below larynx, waist at narrowest point (usually above navel).

Results are for informational purposes and do not constitute medical advice.

How it works

The US Navy circumference method uses a logarithmic formula to estimate body fat from tape measurements. For men: BF% = 495 / (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450. For women: BF% = 495 / (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.22100 × log₁₀(height)) − 450. All measurements are in cm; inch inputs are multiplied by 2.54 first. All logarithm and arithmetic operations run locally in your browser using JavaScript.

Processing runs in your browser

The entire calculation runs in the browser page using pure JavaScript. Our servers are not involved at any point.

Technical specification

The US Navy circumference method was developed by Hodgdon and Beckett at the Naval Health Research Center (1984) and validated against hydrostatic (underwater) weighing. The formula uses circumference measurements and the logarithm of measurement differences. Accuracy is ±3–4 percentage points, similar to skinfold caliper methods. DEXA scanning remains the gold standard for body composition measurement.

Method
US Navy circumference method (Hodgdon & Beckett, 1984)
Accuracy
±3–4 percentage points
Men inputs
Neck, waist, height
Women inputs
Neck, waist, hip, height

Related operations

For a general weight category from your height and weight, try the BMI calculator. To split total weight into estimated lean and fat mass, use the lean body mass calculator. For a reference weight range for your height, see the ideal weight calculator.

Frequently asked questions

What body fat percentage is healthy for men?
Essential fat is 2–5%. Athletic men typically range from 6–13%, fitness level from 14–17%, and the acceptable average is 18–24%. Above 25% is generally classified as obese for men.
How accurate is the Navy circumference method?
The US Navy method has a margin of error of approximately 3–4 percentage points. It is less accurate than DEXA scans but comparable to skinfold caliper measurements and much more accessible.
Where should I measure my waist?
For men, measure around the narrowest part of your abdomen (usually just above the navel). Keep the tape horizontal, breathe normally, and do not suck in your stomach.
Is my data sent to a server?
All calculations are pure JavaScript running in your browser. Our servers are not involved at any point.

Last reviewed September 30, 2026

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