TheFreeTool

Body Fat Calculator

Measure your neck and waist, and your hip if you are a woman, then enter them with your height and weight. The calculator estimates your body fat percentage.

Good to know

This tool gives general information only and is not medical advice. A tape-measure estimate is not a diagnosis. Speak to a doctor or qualified health professional about your own situation.

What it does

  • US Navy tape-measure method
  • Body fat percentage and a fitness category
  • Fat mass and lean mass from your weight
  • Metric (cm, kg) or imperial (inches, pounds)

How to use it

  1. Choose your sex and units.
  2. Enter your height, neck, waist and weight. Add your hip if you are a woman.
  3. Read your estimated body fat, category, fat mass and lean mass.

How are the measurements taken?

Measure your neck just below the larynx, with the tape sloping slightly down. For men, measure the waist at the navel. For women, measure the waist at the narrowest point and the hips at the widest point. Keep the tape snug but not tight and breathe out normally.

The US Navy formula estimates body fat from the difference between waist and neck (plus hip for women) and your height. It is a quick estimate, usually within a few percentage points, and less exact than a body scan. The categories follow common fitness ranges.

Example

A man 175 cm tall, 80 kg, with a 38 cm neck and 90 cm waist has an estimated body fat of about 20.7%. That is about 16.5 kg of fat and 63.5 kg of lean mass, in the average range.

Questions people ask

How accurate is this?
It is an estimate. It can be a few points off, especially for very muscular or very lean people. Measure at the same time of day for comparison.
Why does it ask for hip only for women?
The formula for women includes the hips. The men's formula uses only the neck and waist.
What is a healthy body fat?
It varies with age and sex. Roughly 14% to 24% for men and 21% to 31% for women are common healthy ranges. A doctor can advise on yours.

Disclaimer

This tool is for general information only and is not medical advice. Results are estimates and do not diagnose, treat or replace a doctor, dietitian or other health professional. Talk to a qualified professional before you change your diet, exercise or health routine. You use this tool at your own risk, and TheFreeTool is not liable for any loss or harm that follows. Read the full disclaimer

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