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Body Fat Percentage Calculator (Navy Method)

Estimate body fat percentage using the US Navy tape measure method.

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Results

Body Fat
Fat Mass0
Lean Mass0

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Assumptions

  • The estimate uses the U.S. Navy circumference formula rather than direct body-fat testing.
  • Measurements must be taken consistently at the correct body landmarks for useful comparisons.
  • The method is best used for trend tracking and screening, not for precision body-composition analysis.

Sensitivity preview

Height (ft) -10%: Body Fat 20.20%

Height (ft) Current: Body Fat 17.50%

Height (ft) +10%: Body Fat 15.00%

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About this Body Fat % (Navy)

Knowing your body fat percentage gives a better picture of health than weight alone. A scale can't tell the difference between fat and muscle, but a tape measure can. This calculator uses the official U.S. Navy algorithm based on waist, neck, and height measurements.

Who this calculator is for

  • Adults who want a tape-measure estimate of body fat percentage.
  • People comparing body-fat percentage against scale weight or BMI.
  • Anyone who prefers a waist-and-neck method over calipers or smart scales.

When to use it

  • Use this calculator when tracking body composition with simple tape measurements.
  • Use it to compare estimated body fat across different cut or bulk phases.
  • Use it when BMI alone does not reflect muscle mass or physique changes well.

How to use this calculator

  1. Select Gender (formulas differ significantly).
  2. Enter Height.
  3. Measure and enter Neck circumference (below the larynx).
  4. Measure and enter Waist circumference (at the belly button for men, narrowest part for women).
  5. For women, enter Hip circumference (widest part).

Key assumptions

  • The estimate uses the U.S. Navy circumference formula rather than direct body-fat testing.
  • Measurements must be taken consistently at the correct body landmarks for useful comparisons.
  • The method is best used for trend tracking and screening, not for precision body-composition analysis.

Accuracy and testing

Review formula sources, default test cases, assumptions, unit handling, rounding rules, and changelog for this calculator.

View accuracy page

How this calculator works

The U.S. Navy method relies on the principle that body fat distribution patterns differ between sexes. It uses logarithmic equations comparing the torso circumference (Waist/Hips) to the Neck and Height to estimate total body fat.

Inputs explained

Neck

Measure just below the Adam's apple. Keep the tape flat.

Waist (Men)

Measure across the navel (belly button). Relax, don't suck it in.

Waist (Women)

Measure at the narrowest natural waist point.

Hips (Women)

Measure at the widest part of the buttocks.

Understanding your results

The result is your estimated Body Fat Percentage. Compare this against standard fitness charts (e.g., Men 14-17% is fit, Women 21-24% is fit).

Example scenarios

Male Example

Height 70in, Neck 15in, Waist 34in. Estimated Body Fat: ~16%.

Female Example

Height 64in, Neck 13in, Waist 28in, Hips 38in. Estimated Body Fat: ~26%.

Key Features

  • Official Navy Algorithm
  • Gender Specific Logic
  • No Calipers Needed

Things to Keep in Mind

Less accurate for individuals with extremely low body fat or unique body shapes (e.g. very thick necks from powerlifting).

Tips & Best Practices

  • Measure 3 times and take the average for better accuracy.
  • Measure in the morning before eating or bloating occurs.
  • Use a flexible fiberglass tape measure, not a metal construction tape.

Glossary of Terms

Essential Fat
The minimum amount of fat necessary for basic physical and physiological health.
Lean Body Mass
Total body weight minus fat weight.

Frequently Asked Questions

How accurate is the Navy Method?
It is typically within 3-4% of DEXA scan results for most people. It is more accurate than BMI but less precise than hydrostatic weighing.
Why do women need a Hip measurement?
Women naturally store more fat in the hip and gluteal region due to hormonal differences. The formula accounts for this to avoid overestimating body fat.
What is an 'Essential' fat level?
Essential body fat is required for life functions. Men need ~2-5%, while women need ~10-13% due to reproductive system requirements.
What is a 'Fitness' level body fat?
For men, 14-17% is considered 'Fitness', while 6-13% is 'Athlete'. For women, 21-24% is 'Fitness', and 14-20% is 'Athlete'.
Can I use a metal tape measure?
It is recommended to use a flexible fiberglass or cloth tape measure for body circumferences to get a snug fit against the skin.