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Body Fat Percentage Calculator
This calculator estimates body fat percentage from a few tape measurements using the US Navy method — the same formula the US military has used for decades. It is free, private, and best used to track a trend over time.
⚠️ Rough estimate: tape-measure methods can be off by several percentage points versus lab methods like DEXA. This is not a medical measurement — treat the result as an approximate trend, not a precise reading.
Estimated body fat
Rough estimate — tape methods can be off by several percentage points. Compare repeat measurements taken the same way, not single readings.
🔒 Private: all math runs in your browser. Nothing is sent anywhere, stored, or tracked.
How to measure (consistency matters more than perfection)
- Use a flexible tape, standing relaxed, breathing normally — do not suck in or hold your breath.
- Neck: just below the Adam's apple, tape flat against the skin, not tight.
- Waist: at the narrowest point of the torso, or at the navel if you are unsure. Use the same spot every time.
- Hip (women): at the widest point of the buttocks.
- Measure in the morning and repeat the same way each time — trends beat single readings.
Turn one estimate into a daily plan
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See plans & free trial →Frequently asked questions
How accurate is the US Navy body fat method?
It is a rough estimate. Tape-measure methods can be off by several percentage points versus lab methods like DEXA, because tape cannot separate fat from muscle and results depend on exactly where and how tightly you measure. Use it to track trends, not as a precise reading.
What is a healthy body fat percentage?
Typical healthy ranges are roughly 10–20% for adult men and 18–28% for adult women, with wide individual variation by age and build. Athletes often sit lower; older adults often sit higher. These are broad reference bands, not personal targets.
How do I measure correctly for this calculator?
Use a flexible tape, standing relaxed, not holding your breath. Neck: just below the Adam's apple, tape flat. Waist: at the narrowest point, or at the navel if unsure — be consistent. Hip (women): widest point of the buttocks. Measure in the morning and repeat the same way each time.
Is this body fat calculator private?
Yes. All math runs in your browser. Nothing you enter is sent anywhere, stored, or tracked.
Disclaimer: Rough estimate — tape-measure methods can be off by several percentage points. Not a medical measurement, diagnosis, or treatment guide. Not medical advice — talk to a clinician for personal guidance.