How to use the skinfold body fat calculator
Prepare the values for this calculation
Estimate body-fat percentage from three individual Jackson–Pollock caliper readings and age. Use chest, abdomen and thigh for the male equation; triceps, suprailiac and thigh for the female equation. 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
- Sex used by the published equation: choose Male equation, Female equation. Match this selection to the data you enter.
- Age (years): enter a value at least 18 and no more than 61 and a whole number. Use the unit named in the label or selected above. Do not leave this required field blank.
- Site 1: chest (male) / triceps (female), mm: enter a value at least 0.1 and no more than 200. Use the unit named in the label or selected above. Do not leave this required field blank.
- Site 2: abdomen (male) / suprailiac (female), mm: enter a value at least 0.1 and no more than 200. Use the unit named in the label or selected above. Do not leave this required field blank.
- Site 3: thigh, mm: enter a value at least 0.1 and no more than 200. 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 12.72%. Compare the additional metrics with the primary result; each has its own label and unit.
Compare and keep a useful result
For a controlled comparison, keep every other example input unchanged and change Age (years) from 30 to 33. The resulting Estimated body fat is 13.06%. 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.
Skinfold Body Fat Calculator formula
The three entered folds are summed, then the sex-specific Jackson–Pollock 3-site body-density regression is applied. Siri conversion: body fat % = 495/BD − 450.
Inputs and units
| Input | Format / range | Example |
|---|---|---|
| Sex used by the published equation | Select an option | Male equation |
| Age (years) | minimum 18; maximum 61; whole number | 30 |
| Site 1: chest (male) / triceps (female), mm | minimum 0.1; maximum 200 | 10 |
| Site 2: abdomen (male) / suprailiac (female), mm | minimum 0.1; maximum 200 | 20 |
| Site 3: thigh, mm | minimum 0.1; maximum 200 | 12 |
Worked example
Using the example inputs above, the estimated body fat is 12.72%.
- Estimated body fat
- 12.72%
- Body density
- 1.069759 g/cm³
- Skinfold sum
- 42 mm
- Protocol sites
- Chest + abdomen + thigh
Results and assumptions
This is a regression-based body-composition estimate, not a direct measurement or diagnosis. Caliper technique and site selection materially affect the result. The male study included ages 18–61 and the female study ages 18–55; this calculator does not extrapolate beyond those study age ranges.
Sources and method references
Fix an input or unexpected result
Age (years) is required. Enter age (years) 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.