US Navy Body Fat Calculator
Estimate your body fat percentage using the U.S. Navy circumference method. This method uses tape measurements and is practical for home use.
Tip: Measure at the same time of day, keep the tape snug (not compressing skin), and stand relaxed for consistency.
What is a US body fat calculator?
A US body fat calculator estimates body fat percentage using circumference measurements and a standardized formula developed by the U.S. Navy. Unlike BMI, which only compares weight to height, body fat percentage gives a better picture of body composition by estimating how much of your weight is fat tissue versus lean tissue.
The U.S. Navy method is popular because it is quick, inexpensive, and does not require special equipment beyond a measuring tape. While it is not as precise as a DEXA scan, it is often accurate enough to track progress over time if measurements are taken consistently.
How to take measurements correctly
For men
- Height: Stand barefoot against a wall, looking straight ahead.
- Neck: Measure just below the larynx (Adam's apple), with tape level.
- Waist: Measure at the navel level while relaxed, after normal exhalation.
For women
- Height: Same method as above.
- Neck: Measure just below the larynx, keeping tape horizontal.
- Waist: Measure at the narrowest part of the torso or at navel level if unsure.
- Hip: Measure around the widest part of the hips/glutes.
Small measurement differences can change your estimated body fat percentage. For best results, take 2-3 readings for each site and use the average.
Formula used by this calculator
This tool applies the U.S. Navy equation (in inches). If you enter centimeters, values are converted automatically before calculation:
- Men: %BF = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76
- Women: %BF = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387
If weight is provided, the calculator also estimates:
- Fat mass: body weight × body fat %
- Lean mass: body weight − fat mass
Body fat ranges (general reference)
| Category | Men | Women |
|---|---|---|
| Essential Fat | 2-5% | 10-13% |
| Athletes | 6-13% | 14-20% |
| Fitness | 14-17% | 21-24% |
| Average | 18-24% | 25-31% |
| Obesity | 25%+ | 32%+ |
How to use your result wisely
Treat the number as a trend marker, not a verdict. One reading is less useful than a series over weeks or months. Body composition changes gradually, so watch direction over time instead of day-to-day noise.
- Measure under similar conditions each time (morning, same hydration, same tape).
- Pair body fat tracking with waist size, strength progress, and photos.
- Avoid extreme diets. Sustainable nutrition and resistance training work best.
- Recalculate every 2-4 weeks rather than daily.
Common mistakes that reduce accuracy
- Pushing the tape too tight into skin or leaving it too loose.
- Measuring at inconsistent body landmarks.
- Taking measurements at different times of day with different hydration.
- Comparing your result directly against methods like DEXA without context.
Final thoughts
The US body fat calculator is one of the most practical tools for at-home body composition estimates. It is simple, repeatable, and useful for tracking progress when applied consistently. If your goal is fat loss, muscle gain, or general health improvement, focus on long-term trends and habits rather than chasing a perfect single measurement.