Body Fat Calculator
Estimate your body-fat percentage using height and circumference measurements. Choose US or Metric units and follow the measurement instructions for consistent results.
Results
Enter your measurements and calculate to see an estimate.
Measurement guide
Height
Stand upright with no shoes.
Neck
Measure around the neck just below the larynx. Keep the tape level or slightly downward, snug without compressing the skin.
Male waist / abdomen
Measure horizontally around the abdomen at the level of the navel. Stand relaxed and do not pull the abdomen in.
Female waist
Measure horizontally at the natural waist or narrowest point.
Female hips
Measure around the widest or fullest part of the hips and buttocks.
Keep the tape horizontal, snug but not compressing, and take measurements consistently.
How to calculate body fat percentage
This Body Fat Calculator estimates body-fat percentage from body circumference measurements using the Hodgdon-Beckett equations. It follows a simple flow: measurements go into the equation, the equation estimates body density, and body density is converted into an estimated body-fat percentage.
The calculator supports US and Metric inputs. For calculation, measurements are converted to canonical centimeters first, so the same physical measurements are used regardless of the unit system shown on screen.
Optional weight does not affect the body-fat percentage. If weight is entered, it is used only to estimate fat mass and lean mass from the calculated percentage.
U.S. Navy body fat formula
This calculator uses the Hodgdon-Beckett circumference equations, often referred to online as the U.S. Navy body fat formula.
The current U.S. Navy Body Composition Assessment uses a different procedure, so this calculator should not be used to determine an official Navy BCA result or pass/fail status.
For men, the body fat formula uses height, neck, and abdomen or waist circumference. For women, it uses height, neck, waist, and hips. Measurements in the formulas below are in centimeters and logarithms are base 10.
Body fat percentage for men and women
This body fat percentage calculator uses different measurement paths for men and women because that is how the underlying Hodgdon-Beckett equations were developed.
Body fat calculator for men
The male equation uses height, neck, and abdomen measurement at navel level.
Body fat calculator for women
The female equation uses height, neck, natural waist, and hips.
Body-fat reference ranges vary by source, sex, age, population, and measurement method. An estimated percentage should be interpreted as a reference point rather than a diagnosis.
How to measure body fat at home
Body fat percentage can be estimated at home with a flexible measuring tape and circumference measurements. Men use height, neck, and abdomen or waist measurements, while women use height, neck, waist, and hips. Consistent measurement technique matters because circumference-based estimates are sensitive to tape placement and tension.
How to measure waist, neck, and hips correctly
- Height: Stand upright with no shoes.
- Neck: Measure around the neck just below the larynx, snug without compressing the skin.
- Men - abdomen: Measure horizontally at navel level while relaxed. Do not pull the stomach inward.
- Women - waist: Measure at the natural waist or narrowest point.
- Women - hips: Measure around the widest or fullest part of the hips and buttocks.
Take measurements consistently. Small changes in tape placement or tension can change the estimate.
Frequently asked questions
How accurate is a body fat calculator?
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