Body Fat Percentage Calculator
Body Fat Percentage Calculator works out Body fat and Category from Method, Units and Sex. The default figures on this page give body fat of 15.49 %; change any entry and the result, the working and the sources update together.
Your figures
Updates as you typeHow this is worked out
5 steps
- Weight = 180.0 lb = 81.647 kg
- Height = 177.8 cm = 70 in
- Girth = abdomen - neck = 34 - 16 = 18 in
- %fat = 86.010 log10(18) - 70.041 log10(70) + 36.76 = 15.493%
- ACE category for men: Fitness.
Its 5 worked examples are re-run on every release, last on 15 September 2026. What changed
Sources and references
7 sources
Keep this result
Save it, change one figure, then compare the two
The calculation stays free. Save this scenario, adjust one assumption, save that too, and put them side by side to see exactly what the change costs you. A free account keeps 5 scenarios and 2 comparisons; Personal makes both unlimited and adds exports and private links. Nothing is saved unless you press Save.
What the Body Fat Percentage Calculator calculates
Estimates body-fat percentage by the US Navy tape method, the Deurenberg BMI equation or Jackson-Pollock skinfolds, and reports fat mass, lean mass and the category the result falls in.
How to use this Body Fat Percentage Calculator
Enter Method, Units, Sex and Age. Body fat updates as you type, and “Use a worked example” loads checked figures you can adjust. Change one figure at a time to see what drives the result.
How the result is worked out
Open “How this is worked out” beside the result for the step-by-step calculation behind Body fat, Category and Fat mass.
The method follows Hodgdon J.A. & Beckett M.B., Prediction of percent body fat for U.S. Navy men and women from body circumferences and height, Naval Health Research Center Reports 84-11 and 84-29, Deurenberg P., Weststrate J.A. & Seidell J.C., Body mass index as a measure of body fatness: age- and sex-specific prediction formulas, British Journal of Nutrition 65:105-114, Jackson A.S. & Pollock M.L., Generalized equations for predicting body density of men (Br J Nutr 1978;40:497-504) and Jackson, Pollock & Ward, of women (Med Sci Sports Exerc 1980;12:175-181), Siri W.E., Body composition from fluid spaces and density (1961) and Brozek J. et al., Densitometric analysis of body composition (1963) and ALARACT 046/2023, Notification of new Army body fat assessment methods, reprinting AR 600-9 table B-2 maximum allowable percent body fat.
Navy tape, male: 70 in tall, 34 in abdomen, 16 in neck example
With Method: navy, Units: imperial, Sex: male, Age: 30, the calculator returns Body fat: 15.4934763, Waist-to-height ratio: 0.485714286. This example is checked against an independent source in the test suite.
What you can compare
Change one input at a time to see how it affects Body fat, Category and Fat mass. The inputs you can vary are Method, Units, Sex, Age, Weight and Extra pounds.
Understanding Body fat, Category and Fat mass
Every method here is a regression fitted to a reference population, not a measurement of your body. Each carries a standard error of roughly 3-4 percentage points, and none is a diagnosis. Use a clinician, DXA or hydrostatic weighing if the number matters medically.
Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.
See something wrong? Report a problem with this calculator
Frequently asked questions
How do I calculate my percentage of body fat?
Estimates body-fat percentage by the US Navy tape method, the Deurenberg BMI equation or Jackson-Pollock skinfolds, and reports fat mass, lean mass and the category the result falls in. Open “How this is worked out” beside the result to see each step for your own figures.
Is 20% body fat realistic?
Estimates body-fat percentage by the US Navy tape method, the Deurenberg BMI equation or Jackson-Pollock skinfolds, and reports fat mass, lean mass and the category the result falls in. On the figures this page opens with — age 30 years, weight 180 and height (inches) 10 — the body fat is 15.49%. Put your own figures in their place and the working updates beside the result.
Which body fat calculator is most accurate?
The Body Fat Percentage Calculator follows the stated method, but the result is only as reliable as Method, Units, Sex, Age and Weight and the assumptions shown. Check the working and sources before relying on it for an important decision.
What information do I need for the Body Fat Percentage Calculator?
You need Method, Units, Sex, Age, Weight, Extra pounds, Height and Height (feet). The page opens with default figures that give body fat of 15.49 %, so you can see the scale before entering your own.
What does this Body Fat Percentage Calculator show?
It shows Body fat, Category, Fat mass, Lean (fat-free) mass, Body density, BMI, Method used and Standard error of this method, with the working and any warnings for your entries.
Can I check how the Body Fat Percentage Calculator result was calculated?
Yes. The “How this is worked out” section shows the calculation steps, and the sources section identifies the references used for the method.