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Health Calculators

Body Fat Calculator

Use this body fat calculator to estimate body fat percentage from height, weight, neck, waist, and hip measurements.

Reviewed May 25, 2026EstimateFormula shown

Quick answer

Body Fat Calculator: what it calculates

Body Fat Calculator calculates estimated body fat from sex, weight and height. The core method is Men: 86.010 x log10(waist - neck) - 70.041 x log10(height) + 36.76; women: 163.205 x log10(waist + hip - neck) - 97.684 x log10(height) - 78.387.

ResultEstimated body fat
InputsSex, Weight, Height, Neck, Waist, Hip
FormulaU.S. Navy-style circumference formula

Live calculator

Body fat estimate

Estimated body fat32.9%

U.S. Navy circumference-style estimate from tape measurements.

Fat mass54.3 lb

110.7 lb estimated lean mass.

Measurement value59 in

Used with 66 inches of height in the formula.

Estimate note

Tape-measure formulas can move a lot when measurements change by even a small amount. Use consistent measurement points and treat the result as a tracking estimate, not a clinical body composition test.

Formula

U.S. Navy-style circumference formula

Men: 86.010 x log10(waist - neck) - 70.041 x log10(height) + 36.76; women: 163.205 x log10(waist + hip - neck) - 97.684 x log10(height) - 78.387

All measurements are in inches. Tape estimates are sensitive to measurement technique.

How to use

Steps

  1. Choose sex.
  2. Enter weight and height.
  3. Enter neck and waist measurements.
  4. Enter hip measurement when using the female formula.

Example

Sample calculation

ProfileFemale, 5 ft 6 in
Measurements13 in neck, 32 in waist, 40 in hips
EstimateAbout 34% body fat

Calculator use

Best for

  • Quick estimated body fat from sex, weight and height.
  • Wellness, nutrition, pregnancy, or fitness planning when a rough estimate is enough.
  • Scenario comparisons before changing calorie, macro, or body-measurement assumptions.
  • Planning alongside professional medical or nutrition advice, not as a diagnosis.

Before relying on it

Check first

  • Entering sex, weight and height from different time periods or scenarios.
  • Treating a calculator result as medical advice or a diagnosis.
  • Using stale body, activity, pregnancy, or nutrition inputs when your situation has changed.
  • Ignoring context such as age, medication, training status, medical history, or professional guidance.

Details

What to know before using the result

These notes make the assumptions explicit, especially where the same search query can mean slightly different things.

Measurement qualityTape placement matters

Small tape-measure differences can shift the result, so use consistent landmarks and a non-stretch tape.

Estimate typeCircumference method

This is not the same as DEXA, hydrostatic weighing, or a clinical body composition assessment.

Tracking useCompare like with like

The result is most useful when you measure the same way over time rather than treating one estimate as exact.

Source notes

References used for this calculator

U.S. NavyPublishes body composition assessment guidance with circumference-based body fat estimation tables.Centers for Disease Control and PreventionNotes that BMI does not directly measure body fat, which is why body composition estimates need separate interpretation.

Benchmarks

How to read the result

The calculator is a decision aid, not a fixed rule. Use the output to compare scenarios and document your assumptions.

Tape methodConvenient estimate

Easy to repeat at home, but less precise than clinical body composition tests.

DEXA or clinical testingMore direct

May be useful when accuracy matters for medical or athletic decisions.

Trend over timeMore useful than one reading

Consistent repeated measurements are usually more useful than a single estimate.

Calculator accuracy

Methodology and assumptions

The formula, inputs, example, and limitations are shown so the result is checkable, not just a number in a box.

Formula

Men: 86.010 x log10(waist - neck) - 70.041 x log10(height) + 36.76; women: 163.205 x log10(waist + hip - neck) - 97.684 x log10(height) - 78.387

Inputs used

Sex, Weight, Height, Neck, Waist, Hip

Limitations

Results are estimates for quick planning and should be checked before important financial, legal, tax, health, or business decisions.

Last reviewed

May 25, 2026

Cite this page

Toolkit Shelf. Body Fat Calculator. Retrieved May 25, 2026, from https://toolkitshelf.com/tools/body-fat-calculator

FAQ

Common questions

How does the body fat calculator work?

It applies a U.S. Navy-style circumference equation using height and tape measurements from the neck, waist, and hips.

Is the body fat result exact?

No. Tape-based body fat is an estimate and can change with measurement technique, hydration, posture, and body shape.

Why does hip measurement appear only for female input?

The common U.S. Navy-style female equation uses waist, hip, neck, and height, while the male equation uses waist, neck, and height.