Body fat calculator
Estimate body fat percentage with the US Navy tape method and see where it falls in the ACE categories.
- ๐บ๐ธ US federal & state rules
- See sources
Body fat (US Navy method)
17.5%
Fitness range for men (ACE)
- Category
- Fitness
- Fat mass
- 29.8 lb
- Lean mass
- 140.2 lb
This is an example. Enter your numbers above and press the button to see your own result.
ACE body fat categories, men
| Essential fat | 2 to 5% |
|---|---|
| Athletes | 6 to 13% |
| Fitness | 14 to 17% |
| Average | 18 to 24% |
| Obese | 25% or more |
- Measure the neck just below the larynx, the waist at the navel for men or at the narrowest point for women, and the hips at the widest point. Keep the tape flat and do not pull it tight.
- The tape method has a typical error of about 3 to 4 percentage points against lab tests. Use it to track change over time.
- This is an estimate for general information, not medical advice. Talk to a doctor or registered dietitian before a big change in diet or exercise, especially if you are pregnant or have a health condition.
Show the math
| Height | 70 in |
|---|---|
| Waist - neck | 19 in |
| Formula | 86.010 ร log10(19) - 70.041 ร log10(70) + 36.76 = 17.51% |
What to do next
How it works
The US Navy method estimates body fat from height and a few tape measurements. For men: 86.010 ร log10(waist - neck) - 70.041 ร log10(height) + 36.76. For women: 163.205 ร log10(waist + hip - neck) - 97.684 ร log10(height) - 78.387. All measurements are in inches; centimeters are converted first.
The result is placed in the American Council on Exercise categories: essential fat, athletes, fitness, average and obese.
Things to keep in mind
Measure in the morning, relaxed, with the tape snug but not pressing the skin. Take each measurement twice and use the average. A half inch on the waist moves the result by about 1 point.
Lab methods such as DEXA are more precise. The tape method is best for watching your own trend. This page is general information, not medical advice.
Sources
- Hodgdon JA, Friedl KE. Development of the DoD body composition estimation equations (NHRC Report 99-2)Checked 2026-10-19
- Hodgdon JA, Beckett MB. Prediction of percent body fat for U.S. Navy women from body circumferences and height (NHRC Report 84-29)Checked 2026-10-19
- American Council on Exercise: Percent body fat calculator and categoriesChecked 2026-10-19
Frequently asked questions
How accurate is the Navy body fat method?
In the original Navy studies the typical error was about 3.5 percentage points for men and 3.6 for women compared with underwater weighing. It is less accurate at very high or very low body fat.
What is a healthy body fat percentage?
ACE puts average at 18 to 24% for men and 25 to 31% for women, and fitness at 14 to 17% for men and 21 to 24% for women. Obese starts at 25% for men and 32% for women.
What is the body fat of a 5 ft 10 in man with a 15 in neck and 34 in waist?
The Navy formula gives about 17.5%, which sits in the fitness range for men.
Why do women need a hip measurement?
Women carry more fat at the hips, so the Navy equation for women adds hip circumference to the waist before subtracting the neck.