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Body Fat Calculator

Estimate your body fat percentage using the U.S. Navy method. Enter height, waist, neck, and hip measurements for an accurate assessment.

How to Calculate Body Fat Percentage

This calculator uses the U.S. Navy circumference method, a validated formula that estimates body fat from simple tape measurements. It's the same method used by the U.S. military for fitness assessments.

The Navy Method Formula

Men: BF% = 86.010 × log10(waist - neck) - 70.041 × log10(height) + 36.76

Women: BF% = 163.205 × log10(waist + hip - neck) - 97.684 × log10(height) - 78.387

All measurements in centimeters.

How to Take Measurements

  • Waist: At the navel, standing relaxed (don't suck in)
  • Neck: Below the Adam's apple at the narrowest point
  • Hip (women only): At the widest point of buttocks, feet together
  • Height: Without shoes, standing straight

Body Fat Categories

  • Essential fat: Men 2-5%, Women 10-13% — minimum for survival
  • Athletes: Men 6-13%, Women 14-20%
  • Fitness: Men 14-17%, Women 21-24%
  • Acceptable: Men 18-24%, Women 25-31%
  • Obese: Men 25%+, Women 32%+

Why Body Fat Matters More Than Weight

Two people can weigh the same but have very different body compositions. Someone with 15% body fat carries more muscle (and less health risk) than someone at 30% body fat, even at the same weight. Body fat percentage gives a more accurate picture of health than BMI or scale weight alone.

Consider using this alongside our BMI Calculator and TDEE Calculator for a complete fitness assessment.

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Frequently Asked Questions

How accurate is the Navy body fat method?

The U.S. Navy method is accurate to within 1-3% of DEXA scans for most people. It tends to be less accurate for very lean or very obese individuals.

What body fat percentage is healthy?

For men: 10-20% is considered fit, 20-25% acceptable. For women: 18-28% is fit, 28-32% acceptable. Essential fat is 2-5% for men and 10-13% for women.

Where do I measure my neck circumference?

Measure around the narrowest point of your neck, just below the larynx (Adam's apple), keeping the tape level.

Where do I measure my waist?

Measure at the narrowest point of your natural waist, typically at the navel level. Stand relaxed and don't suck in your stomach.

Where do I measure hip circumference?

Women only: Measure at the widest point of your hips/buttocks with feet together.

What is the most accurate body fat measurement?

DEXA (Dual-Energy X-ray Absorptiometry) is the gold standard. Hydrostatic weighing and Bod Pod are also very accurate. The Navy method is the best free estimation.