Estimate your body fat percentage from a tape measure and your height and weight, in inches and pounds or centimetres and kilograms. You also get your fat mass and lean mass, and a simple recomposition plan if you want to change your body fat.
Body Fat Classification
Body Composition Breakdown
About Your Results
Understanding the Navy Method
This calculator uses the U.S. Navy body fat formula, which is based on circumference measurements. While not as accurate as DEXA scans or hydrostatic weighing, it provides a reasonable estimate (±3-4% accuracy) that correlates well with more precise methods.
- Males: Uses neck and waist measurements along with height
- Females: Uses neck, waist, and hip measurements along with height
- Accuracy: Best when measurements are taken consistently at the same locations
- Limitations: May be less accurate for very muscular or very lean individuals
Method Comparison
| Calculation Method | Body Fat % | Fat Mass | Lean Mass | Notes |
|---|
Body Composition Distribution
| Health Metric | Your Value | Recommended Range | Status |
|---|
Detailed Analysis
Activity-Specific Recommendations
Current Body Composition
Goal Body Composition
Projected Body Composition Progress
Current vs Goal Composition
Current
Goal
Milestone Timeline
| Training Phase | Duration | Focus | Calories | Key Actions |
|---|
Recomposition Strategy
Training Recommendations
Nutrition Guidelines
Progress Tracking
What this body fat calculator does
- Basic Estimation: body fat percentage from waist, neck, height (and hip for women) using the circumference method commonly called the US Navy method, with fat mass and lean mass.
- Advanced Analysis: shows the Navy estimate next to a BMI-based estimate, averages them, and estimates resting calorie use from your lean mass.
- Recomposition Plan: from your current and goal weight and body fat, shows the fat loss and lean mass change involved, a weekly rate, and example calorie and protein targets.
How it is calculated
The Navy method uses the base-10 logarithm of body measurements in inches. For men it uses waist minus neck and height; for women it uses waist plus hip minus neck and height. It was developed by Hodgdon and Beckett at the US Naval Health Research Center in 1984. The BMI-based estimate is 1.20 × BMI + 0.23 × age, minus 16.2 for men or 5.4 for women.
Worked example: a 30-year-old man, 70 in tall, with a 34 in waist and 15.5 in neck gets about 10.1% body fat from the Navy method. At the same time, the BMI-based estimate for him is about 21.7%. The two methods can disagree a lot, which is why neither should be treated as a measurement.
Body fat categories used here
| Category | Men | Women |
|---|---|---|
| Essential fat | Below 6% | Below 14% |
| Athletic | 6% to below 14% | 14% to below 21% |
| Fitness | 14% to below 18% | 21% to below 25% |
| Average | 18% to below 25% | 25% to below 32% |
| Above average | 25% or more | 32% or more |
Things to keep in mind
Tape-measure methods are estimates and can be less accurate for very muscular or very lean people. Measure at the same spots each time and compare trends, not single readings. The calculator asks for the waist to be larger than the neck measurement. This calculator is for general information only and is not medical advice. If you have questions about your result, talk with your health care provider.
Frequently asked questions
Where do I measure?
Measure your neck, waist and (for women) hips with a flexible tape, snug but not tight. Use the same method each time.
Why do the two estimates differ?
The Navy method uses body shape, while the BMI-based method uses weight and height only. Neither measures body fat directly.
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