Body Fat Calculator
Estimate your body fat percentage using the U.S. Navy method based on your body measurements.
Basic Info
Measurements (cm)
Calculator guide
Body Fat Calculator
Estimate body-fat percentage from the measurements and personal details requested on the page. The result depends on the selected equation and measurement quality, so it should be read as an estimate rather than a precise body composition test.
How to use the calculator
- 1Choose the units and enter every requested measurement carefully, following any diagram or field label.
- 2Select the personal profile options requested by the calculator and run the estimate.
- 3Read the percentage with the method in mind; use a validated clinical or fitness assessment if greater accuracy is needed.
Important details to understand
1.Start with the right inputs
Check every number, date, unit, and selected mode before calculating. A correct formula can still give a misleading answer when an input is missing, entered in the wrong unit, or based on a different time period.
2.Know what the calculation includes
The method below describes what this tool uses. Real situations can involve extra rules, costs, calendar conventions, or personal details that are not part of the form, so compare the assumptions with your actual question.
3.Read the unit and rounding
Look at the label as well as the displayed number. Rounding can change the last digits, and results in different units or time periods are not directly comparable until you convert them consistently.
4.Treat the result as a useful check
Use the output to understand a calculation, explore a scenario, or make an initial estimate. When a result affects a formal deadline, a health decision, a contract, or a large payment, confirm it with the relevant source or qualified professional.
How the calculation works
The tool applies its built-in body-fat equation to submitted values. Some methods use height, weight, age, sex, or circumference measurements; the exact inputs determine which formula applies. It does not scan tissue or measure fat directly.
A worked example
A circumference-based estimate can change when a tape is placed differently, even if body composition has not changed.
When this calculator is useful
Track rough changes over time when you repeat the same measurement method under similar conditions.
Planning ahead
Try a few realistic input values to see how a change in an amount, measurement, date, or rate affects the answer.
Learning the method
Follow the explanation and example to understand which inputs matter and how they are combined.
Checking your own work
Compare the result with a hand calculation, a worksheet, or a trusted source when you need an independent sense check.
Explaining a result
Keep the original inputs and units with the output so another person can understand what was calculated.
Tips for a more reliable answer
- Enter the values from the same source and keep units consistent throughout the calculation.
- Check that you selected the mode or option that matches the question you are trying to answer.
- Use the worked example to confirm you understand the inputs and the kind of result the tool returns.
- Save the inputs with the result so you can review or repeat the calculation later.
Limitations and assumptions
Equations can be inaccurate for some bodies and populations, and small input errors can shift the output. The number is not a diagnosis or a measure of worth. Consult a qualified professional for health questions.
Every result depends on the information entered and the method described above. The calculator cannot confirm that the inputs are complete or that its assumptions match a particular provider, policy, location, body, or real-world situation.
Frequently asked questions
Is this as accurate as a scan?
No. It is an equation-based estimate and not a direct measurement.
Why does consistency matter?
Tape placement and posture can change circumference inputs and therefore the calculated estimate.
Can I use the result to diagnose a health problem?
No. A clinician should interpret health risks using appropriate information.
Why might my result differ from another calculator?
Tools can use different assumptions, units, date conventions, included costs, or rounding rules. Compare the inputs and method descriptions before deciding that one result is wrong.
What should I check if the answer looks wrong?
Review the selected mode, each entered value, the units, and any optional fields. Then compare a simple example with the method described in this guide.
Can I rely on the result for an official or high-impact decision?
Use the result as an estimate or explanation and check the limitations listed for this tool. Confirm important decisions with the relevant official source or a qualified professional.