🏃 Body Fat Calculator

Estimate body fat percentage using the US Navy circumference method.

🏃 Body Fat % Calculator (US Navy Method)

Measure at the widest point. All measurements in cm.
Measure at the widest point. All measurements in cm.
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Related Guide
Body Fat Percentage Explained: The US Navy Method
Why body fat beats BMI for body composition, and the healthy ranges.
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What is the Body Fat Calculator?

This calculator estimates your body fat percentage using the US Navy circumference method, which uses tape-measure measurements instead of expensive equipment. Enter your height, neck and waist circumference (plus hip circumference for women), and weight, and it returns your estimated body fat percentage, category, and fat mass in kilograms.

How to Use It

Select the Male or Female tab, measure your neck and waist at their widest points with a tape measure (add hip measurement for the female tab), and enter your height and weight. Click "Calculate" to see your estimated body fat percentage, whether you fall into Essential, Athlete, Fitness, Average, or Obese category, and your total fat mass.

When to Use It

Use it to track body composition changes over time alongside a diet or training program, since body fat percentage often tells a more useful story than weight alone when you're building muscle while losing fat. It's also useful when BMI gives a misleading result, such as for muscular athletes who register as "overweight" by BMI despite low body fat.

Who Benefits

Athletes and gym-goers tracking body composition, dieters who want a metric beyond the scale, and anyone curious how their body fat compares to standard fitness categories for their sex. For higher precision, a DEXA scan or hydrostatic weighing beats any at-home method, including this one.

Frequently Asked Questions

This calculator uses the US Navy method, which requires circumference measurements at the waist, neck, and (for women) hips. The formula was developed by the US Navy for quick field assessment and is accurate within 3–4% for most people.
For men: Essential fat 2–5%, Athletes 6–13%, Fitness 14–17%, Average 18–24%, Obese 25%+. For women: Essential fat 10–13%, Athletes 14–20%, Fitness 21–24%, Average 25–31%, Obese 32%+. Women naturally carry more essential fat due to hormonal functions.
Body fat percentage is a more direct measure of body composition than BMI. BMI doesn't distinguish between muscle and fat, so a muscular athlete might be "overweight" by BMI but have excellent body fat percentage. For body composition assessment, body fat % is more informative.