Fitness

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Body Fat Calculator.

Estimate body fat percentage using measurements

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US Navy Method

This calculator estimates body fat from your height and a few circumference measurements, using the formula developed for the US Navy. All you need is a tape measure.

Body Measurements

Your Body Composition

Body fat percentage

20.1%

Average

Fat mass

14.1 kg

Lean mass

55.9 kg

Body Fat Categories

Men

  • Essential fat: 2-5%
  • Athletic: 6-13%
  • Fitness: 14-17%
  • Average: 18-24%
  • Above average: 25%+

Women

  • Essential fat: 10-13%
  • Athletic: 14-20%
  • Fitness: 21-24%
  • Average: 25-31%
  • Above average: 32%+

Measurement Tips

  • Measure in the morning, before eating and after using the bathroom.
  • Keep the tape snug against the skin without compressing it.
  • Measure the same spots each time so results stay comparable.
  • Take each measurement two or three times and use the average.
  • This is an estimate; methods like DEXA scans are more precise.

Cite this calculator

Canonical URL: https://mathify.one/zh/fitness/body-fat

Cite as: Mathify. (2026). 体脂计算器. https://mathify.one/zh/fitness/body-fat

Use Cases

Track fitness progress

Regularly measure your body fat percentage to see how your diet and exercise routine are affecting your body composition over time.

Example: Measure monthly and log results to see a downward trend as you lose fat.

Set realistic fitness goals

Use your estimated body fat percentage to set achievable targets based on healthy ranges for your gender and age.

Example: If you're at 25% body fat, aim for 20% as a realistic goal.

Frequently Asked Questions

How does the Body Fat Calculator estimate body fat percentage?
This calculator uses simple tape measurements (typically waist, neck, and height for men; waist, hip, neck, and height for women) to estimate body fat percentage. It applies standard formulas like the U.S. Navy method, which are based on anthropometric data and provide a reasonable estimate without needing specialized equipment.
What measurements do I need to use this calculator?
You'll need a flexible tape measure. For men, measure your waist and neck circumference, and your height. For women, measure your waist, hip, and neck circumference, and your height. Ensure measurements are taken at the correct anatomical points for accuracy.
How accurate is this body fat estimate?
The estimate is a good approximation for most people, but it can vary based on factors like age, fitness level, and body composition. It's not as precise as methods like DEXA scans or hydrostatic weighing. Use it as a tracking tool to monitor trends over time rather than an absolute measure.

Tips & Common Mistakes

Tips

  • Take measurements at the same time of day, preferably in the morning before eating or drinking, for consistent results.
  • Use a flexible, non-stretchable tape measure and ensure it's snug but not compressing the skin.
  • Repeat each measurement twice and take the average to reduce errors.
  • Track changes over weeks or months rather than day-to-day, as body fat can fluctuate with hydration and other factors.

Common Mistakes to Avoid

  • Measuring over clothing or bulky undergarments, which adds extra circumference and skews results.
  • Pulling the tape too tight or too loose, leading to inaccurate measurements.
  • Using the wrong anatomical landmarks, such as measuring the waist at the belly button instead of the narrowest point.

Last updated: August 13, 2026