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Body Fat (Navy Method) Calculator

Work out body fat (navy method) instantly with clear inputs, formula shown and shareable results.

About Body Fat (Navy Method) Calculator

The US Navy tape method estimates body fat from circumferences using logarithmic regressions - waist and neck for men, with hips added for women - plus height. An 85 cm waist, 38 cm neck and 178 cm height gives about 18% for a man. It typically agrees with hydrostatic weighing within 3-4 percentage points, and depends heavily on consistent tape placement.

Formulas

Navy formula, men

%fat = 495 / (1.0324 - 0.19077 log10(waist - neck) + 0.15456 log10(height)) - 450

Navy formula, women

%fat = 495 / (1.29579 - 0.35004 log10(waist + hip - neck) + 0.221 log10(height)) - 450

Worked example

With the default values below, Body Fat (Navy Method) Calculator returns Estimated Body Fat of 16.44%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Waist circumference at the navelminimum 30 cm
85 cm
Neck circumferenceminimum 20 cm
38 cm
Heightminimum 100 cm
178 cm
Sexone of Male, Female (hip measurement replaces part of the formula)
Male

Results

Estimated Body Fat
16.44%
Fat Mass At An 80 kg Body Weight
13.15 kg
Lean Mass Percentage
83.6%
Category
Average

Step by step

  1. 1Values used
  2. 2Navy formula, men
  3. 3Navy formula, women
  4. 4Estimated Body Fat= 16.44
  5. 5Fat Mass At An 80 kg Body Weight= 13.15 kg
  6. 6Lean Mass Percentage= 83.6
  7. 7Category= Average

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • These figures are population-average estimates, not a medical assessment or diagnosis. Body composition equations carry errors of several percentage points, and healthy ranges vary with age, ethnicity, muscularity and medical history. Discuss weight or body composition goals with a qualified clinician or dietitian.
  • This is an estimate for general information and not professional medical advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

These figures are population-average estimates, not a medical assessment or diagnosis. Body composition equations carry errors of several percentage points, and healthy ranges vary with age, ethnicity, muscularity and medical history. Discuss weight or body composition goals with a qualified clinician or dietitian.

Frequently Asked Questions

Where exactly should I measure?

Waist at the narrowest point for women and at navel height for men, neck just below the larynx, tape snug but not compressing.

How accurate is the tape method?

Standard error of about 3-4 percentage points against DEXA. It tracks change over time well provided measurement technique stays constant.

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