Body Fat Estimator.
Professional estimation of body composition using the US Navy tape-measure method.
Girth & Height Metrics
Clinical Composition Protocols
The US Navy Body Fat formula is widely recognized as the most accurate tape-measure based estimation method. It analyzes the relationship between your height and girth to differentiate between adipose tissue and lean mass.
Measurement Precision
Ensure measurements are taken against the skin, not over clothing. The waist measurement should be taken at the narrowest point for women and at the navel for men.
Metabolic Impact
Lean mass is metabolically active. Increasing your lean mass ratio significantly improves your resting metabolic rate (BMR).
About the Body Fat Estimator
Professional estimation of body composition using the US Navy tape-measure method. Enter your values in the fields above and the result updates immediately — there is nothing to submit or wait for.
The Body Fat Estimator runs entirely in your browser. There are no server calls, no loading states, and no third-party services involved. This means results are instant, and anything you type stays on your device. You can close the tab at any point and nothing you entered has been saved or transmitted anywhere.
How to get accurate results
Enter your values in the input fields above. Most fields accept whole numbers and decimals. Where units matter — such as inches versus millimetres, or miles versus kilometres — check that you are using the correct unit for the value you are entering.
If you get an unexpected result, check your inputs one at a time. Most errors come from a single transposed digit or an incorrect unit selection, not from the formula itself.
Your data stays private
This tool has no account system and does not log what you type. When you close or refresh the page, everything you entered is gone. It is safe to use for sensitive figures — business numbers, personal health data, financial projections — without any privacy concern.
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Common Questions
Does the Body Fat Estimator need an internet connection to calculate?
Once the page has loaded, no. The Body Fat Estimator runs in your browser using JavaScript. The calculation happens on your device — not on a server — so results appear immediately and work offline once the page is cached.
Is my data private when I use this tool?
Yes. We do not collect, store, or transmit the values you enter. There is no account system, no analytics capturing your inputs, and no database on the other end receiving your data. When you close the tab, everything you typed is gone.
Who uses the Body Fat Estimator?
Anyone who needs a fast, reliable answer without signing up for an account or installing software. The tool is useful for professionals who want a quick sanity check, students working through problems, and anyone who prefers doing the math properly rather than estimating.
When to use this calculator
The Body Fat Estimator is useful whenever you need the correct answer rather than a rough estimate. A common mistake is approximating values that a tool can compute exactly in seconds — particularly in contexts where the result feeds into another decision, such as setting a price, sizing a component, or planning a budget.
Use it as a first check before committing to a figure, or as a way to verify a result you have already calculated by hand. The tool is free, there is no limit on how many times you can use it, and the result is the same every time for the same inputs.