Body Fat Calculator
Estimate body fat with just a tape measure.
Measure on bare skin with a soft tape: neck below the Adam's apple, waist at the navel, hips at the widest point (women).
Estimated body fat
For information only — not a diagnosis or medical advice. Nothing you enter is sent or stored.
How to use Body Fat Calculator
- Measure your neck, waist (and hips for women) with a soft tape.
- Enter the measurements with your height and weight.
- Click “Estimate body fat” to see your percentage, category, fat mass and lean mass.
Frequently asked questions
How accurate is the Navy method?
It's usually within a few percentage points of lab methods for most people — good for tracking change over time with the same measuring routine.
How do I measure correctly?
Measure on bare skin, relaxed, not sucking in. Neck just below the Adam's apple, waist at the navel (men) or narrowest point (women), hips at the widest point.
Can this replace a doctor?
No. This tool gives general estimates and self-checks for information only. It does not diagnose anything. Please see a qualified health professional for medical advice, and seek urgent care if you feel unwell.
Is Body Fat Calculator free?
Yes. Body Fat Calculator is free to use with no sign-up and no watermark.
Is my information saved or sent anywhere?
No. Everything is calculated in your browser. Nothing you enter is sent to a server or stored.
Does it work on my phone?
Yes. It works in any modern browser on Windows, Mac, Linux, Android and iPhone. Very large files may be slow on older phones.