How to use the army body fat calculator
Prepare the values for this calculation
Estimate body-fat percentage using the circumference equations documented in U.S. Army materials. This calculator is clearly labeled as a circumference estimate, not a determination of current Army compliance. Use the formula below to check that it answers your question. Read the input units before transferring figures from a statement, measurement or dataset.
Enter and check each input
- Equation: choose Male, Female. Match this selection to the data you enter.
- Height (in): enter a value at least 30 and no more than 100. Use the unit named in the label or selected above. Do not leave this required field blank.
- Neck circumference (in): enter a value at least 5 and no more than 40. Use the unit named in the label or selected above. Do not leave this required field blank.
- Waist circumference (in): enter a value at least 10 and no more than 100. Use the unit named in the label or selected above. Do not leave this required field blank.
- Hip circumference (in, female equation): enter a value at least 10 and no more than 100. Use the unit named in the label or selected above. Do not leave this required field blank.
The input table gives a complete example. Keep units and time periods consistent across related fields.
Calculate and resolve any input error
Choose Calculate after entering the values. Changes also update the answer after a short pause. If an error appears, follow its message, correct the field and calculate again. Reset restores the example values.
Interpret the answer
Check Estimated body fat first. With the unchanged example inputs, it is 17.51%. Interpret it using the formula and assumptions on this page.
Compare and keep a useful result
For a controlled comparison, keep every other example input unchanged and change Height (in) from 70 to 77. The resulting Estimated body fat is 14.61%. This illustrates the equation’s response to that input, rather than a forecast of real events.
Read the chart’s axis labels and data table. A scenario curve changes one stated input while holding the others fixed; it does not add external observations. Use Download graph to save an available chart as a PNG.
Use Copy result or Download CSV to keep the answer. Share tool shares the page address without placing your input values in the URL. Recheck inputs and assumptions before using the result for a decision.
Army Body Fat Calculator formula
Male: 86.010×log10(waist−neck) − 70.041×log10(height) + 36.76. Female: 163.205×log10(waist+hip−neck) − 97.684×log10(height) − 78.387, with inches.
Inputs and units
| Input | Format / range | Example |
|---|---|---|
| Equation | Select an option | Male |
| Height (in) | minimum 30; maximum 100 | 70 |
| Neck circumference (in) | minimum 5; maximum 40 | 15 |
| Waist circumference (in) | minimum 10; maximum 100 | 34 |
| Hip circumference (in, female equation) | minimum 10; maximum 100 | 40 |
Worked example
Using the example inputs above, the estimated body fat is 17.51%.
- Estimated body fat
- 17.51%
Results and assumptions
Circumference estimate only; do not use this page to determine current Army policy compliance.
Fix an input or unexpected result
Height (in) is required. Enter height (in) using the format and bounds in the input table. Zero and an empty field are different: use zero only if it is allowed and represents your data.
If your answer differs from the example, choose Reset and compare every field, including selected units and options. Check percentage versus decimal entry and whether values describe the same period. Round only the final displayed answer when reproducing the formula.
If a discrepancy remains, report the calculator issue with the page address, non-sensitive example inputs, actual result, expected result and a reference for your calculation.