TopToolsAiEstimate your body fat percentage using the US Navy tape-measure method — just your height, neck and waist (plus hip for women). See where you fall on the standard fitness ranges instantly, no gym scale needed. A man standing 175cm tall with a 90cm waist and 38cm neck comes out around 19%, in the Fitness range, while the same neck measurement paired with a 105cm waist pushes the estimate up near 28%, into the Obese range — the method was originally developed for US Navy recruitment physicals in the 1980s as a cheap alternative to skinfold calipers.
Last updated: 1 Sep 2026
How to use Body Fat Calculator
- Select your gender and enter your height in centimeters.
- Measure and enter your neck and waist (and hip, for women) in centimeters.
- Click "Calculate" to see your estimated body fat percentage using the US Navy method.
Frequently asked questions
How accurate is the Navy method?
It's a solid estimate for most people, typically within a few percent of more precise methods like DEXA scans, but less accurate for very lean or very heavy individuals.
Why does the calculator ask for hip measurement for women?
The Navy formula for women includes hip circumference because fat distribution differs by gender, improving accuracy.
Where exactly should I measure my waist and neck?
Measure your neck just below the larynx (Adam's apple), and your waist at navel level, keeping the tape snug but not compressing the skin.
Why is my result different from my gym's scale?
Smart scales use bioelectrical impedance, which can vary with hydration levels — the tape-measure method used here tends to be more consistent day-to-day.
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