Body fat calculator

Estimate your body fat percentage with tape measurements.

Last updated: January 9, 2026

Built and maintained by Aaron Jegla

Use the U.S. Navy method with height, waist, neck, and hip measurements to estimate body fat percentage. You will also see fat mass and lean mass, plus category ranges to keep results in context.

Measurement guide

Quick tape placement tips before you start.

  • Tape setup: Soft tape, level, snug, no skin compression.
  • Neck: Just below the larynx, shoulders relaxed.
  • Waist: Men at the navel; women at the narrowest point.
  • Hip (women): Widest point, tape level all around.

Body fat details

Switch units and we will convert your inputs automatically.

The U.S. Navy method uses different measurements for men and women.

Measurements

Use your current height without shoes.

Weight is used to estimate fat and lean mass.

Measure just below the larynx with the tape level.

Men: measure at the navel. Women: measure the narrowest point.

Women only: measure the widest point of the hips.

For adults 18+ using standard tape measurements.

Not for pregnancy or clinical diagnosis. Explore our health calculators.

How to use this calculator
  1. Select imperial or metric and choose male or female.
  2. Enter height, weight, neck, waist, and hip if applicable.
  3. Click Calculate to see body fat percentage and category.

Measure with the tape snug but not compressing skin.

Summary

Based on the U.S. Navy body fat method.

Body fat percentage

0%

Category

--

Fat mass

--

Lean mass

--

Category range: --

Body fat scale

Scale runs from 0% to 50% body fat.

Sources: U.S. Navy body fat formula overview, ACE body fat category ranges

Method review: Formula and category ranges are based on publicly available standards from the U.S. Navy and the American Council on Exercise. No personalized medical advice is provided.

Assumptions: Adult tape measurements taken level and consistent. The U.S. Navy method uses waist and neck for men, plus hip for women. For higher accuracy, compare with a clinical method like DEXA or skinfold testing.

Disclaimer: Estimates only and not medical advice. Use results as a screening tool and talk with a healthcare professional if needed.

Body fat category ranges

Ranges shown are general guidance from the American Council on Exercise.

Category Men Women
Essential fat 2-5% 10-13%
Athletes 6-13% 14-20%
Fitness 14-17% 21-24%
Average 18-24% 25-31%
Obese 25%+ 32%+

Terminology reflects ACE reference ranges and is used for classification only.

How this compares to other methods

  • DEXA: clinical gold standard.
  • Skinfold calipers: technician-dependent.
  • BMI: weight-based proxy, not body fat.
  • Navy method: tape-based estimate using circumference measurements.

How this calculator works

It applies the U.S. Navy tape formula and then estimates fat and lean mass.

U.S. Navy method for men

Body fat % = 86.010 * log10(waist - neck) - 70.041 * log10(height) + 36.76

All measurements are in inches. Waist is measured at the navel.

  • Height is your total height in inches.
  • Neck and waist are tape measurements.
U.S. Navy method for women

Body fat % = 163.205 * log10(waist + hip - neck) - 97.684 * log10(height) - 78.387

All measurements are in inches. Waist is the narrowest point and hip is the widest point.

  • Measurements are converted to inches first.
  • Hip is required for the female formula.
Fat mass and lean mass

Fat mass = weight * body fat %

Lean mass = weight - fat mass

Weight is only used for the mass breakdown, not for the body fat percent itself.

Body fat calculator FAQs

Click a question to expand the answer.

Which body fat formula does this calculator use?

This calculator uses the U.S. Navy tape method with height, waist, neck, and hip measurements for women.

Do I need a scale to use this?

The body fat percent is based on tape measurements. Weight is only used to estimate fat mass and lean mass.

Where should I measure my waist, neck, and hips?

Measure your neck just below the larynx, your waist at the navel (men) or the narrowest point (women), and your hips at the widest point if needed.

How accurate is the U.S. Navy method?

It is an estimate that can vary with tape placement, hydration, and body shape. Use it for trends, not a clinical diagnosis.

Is this calculator ok for teens or pregnancy?

No. This calculator is intended for adults 18 or older and is not designed for pregnancy.

Why do other calculators show different results?

Different tools use different formulas, body measurements, and rounding rules. Consistent tape placement matters most.

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