Body Fat Calculator
How it worksEstimate body fat % with the US Navy method
Your details
Estimated body fat %
Tape measurements in centimetres. Measure snug, not compressing soft tissue.
Body fat
16.2 %
Category: Fitness
About this tool
Body fat percentage estimates how much of your mass is fat versus lean tissue. It can add context that weight and BMI alone miss — especially if you lift.
The US Navy method uses tape measurements and a log formula. It is popular because it needs no calipers or DEXA, but results can be off by several percentage points.
Measure consistently (same time of day, relaxed posture, tape snug but not compressing soft tissue) if you want to track trends.
How it works
- Set sex and height in Your details.
- Add neck and waist (plus hips if female) in the calculator.
- We apply the Navy log formula and map the result to common adult category bands.
Practical tips
- Measure neck just below the larynx; waist at the navel (or narrowest point — stay consistent).
- For women, hips are the widest point of the buttocks.
- Use trends over weeks, not a single reading, to judge progress.
Frequently asked questions
How accurate is the Navy method?
It is a field estimate. Compared with DEXA or Bod Pod it can miss by a few points, especially at extremes of body composition. Great for trends; imperfect for absolute truth.
Is lower always better?
No. Essential fat is required for health. Very low levels — especially for women — can disrupt hormones and performance. Aim for a sustainable range with a professional if unsure.
Why do I need hip measurement?
The female Navy equation includes hips. The male equation uses waist and neck only.
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Disclaimer: These tools provide general estimates only. They are not medical advice. For health conditions, pregnancy, or personalised nutrition, speak with a qualified professional.