Body Fat Calculator

Estimate your body fat percentage from simple tape measurements.

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Body Fat Calculator: The Complete Guide

Estimate your body fat percentage with just a tape measure. Enter your height, neck, and waist measurements — plus hip for women — to get your body fat percentage and fitness category using the U.S. Navy method.

Who the Body Fat Calculator is for

People tracking fitness who want a body-fat estimate without calipers or a special scale.

How to use the Body Fat Calculator

  1. Type your values into the fields above — pick your currency or units where the calculator offers them.
  2. Results update automatically as you type; there's no submit button and nothing is sent to a server.
  3. Adjust any input to compare scenarios, then copy the result with a single click.

How it works

The U.S. Navy method uses log-based equations on body circumferences: for men it takes waist and neck; for women it adds hip. Measurements are taken in centimetres (inches are converted automatically).

Features

  • U.S. Navy tape method
  • Body fat % and category
  • Metric or imperial
  • No special equipment

How the Navy method works

The U.S. Navy circumference method estimates body fat from the relationship between your height and key girth measurements. It's free, repeatable, and reasonably accurate for most people — far more practical than calipers. For the best results, measure relaxed, at the same spots each time, and avoid pulling the tape tight.

Frequently Asked Questions

How accurate is this estimate?

Within a few percent for most people when measured carefully. It's a screening estimate, not a DEXA-scan-level measurement.

Where do I measure?

Neck below the larynx, waist at the navel for men (narrowest point for women), and hips at the widest point for women. Keep the tape level and snug, not tight.

Is this calculator free and private?

Yes. It's completely free with no signup, and every calculation runs locally in your browser, so your numbers never leave your device.

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