Calculate Your Body Fat % (U.S. Navy Formula)
Enter your measurements below. This calculator uses circumference-based equations developed by the U.S. Navy.
What Is the Navy Method Body Fat Calculator?
The Navy Method Body Fat Calculator estimates your body fat percentage using simple body measurements instead of expensive scans. It is based on formulas adopted by the U.S. Navy, and it’s popular because it is fast, repeatable, and practical for regular check-ins.
Unlike BMI, which only uses height and weight, the Navy method uses circumference measurements to better capture body composition differences. For many people, that makes it more useful for tracking fitness progress.
How to Measure Correctly
1) Height
Stand straight without shoes, heels together, and look forward. Record your height in inches or centimeters.
2) Neck Circumference
Measure just below the Adam’s apple (larynx), with the tape level around the neck. Do not pull the tape too tight.
3) Waist/Abdomen Circumference
For the Navy formula, measure at the navel (belly button) level, relaxed after a normal exhale. Keep the tape horizontal and snug, not compressing skin.
4) Hip Circumference (Women)
Measure around the widest part of the hips/glutes while standing naturally with feet together.
Navy Body Fat Formula
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
These equations are originally calibrated in inches. If you enter centimeters, the calculator automatically converts your values first, then runs the same formula.
How to Interpret Your Result
Common body fat categories for men
- Essential fat: 2–5%
- Athletes: 6–13%
- Fitness: 14–17%
- Average: 18–24%
- Obese: 25%+
Common body fat categories for women
- Essential fat: 10–13%
- Athletes: 14–20%
- Fitness: 21–24%
- Average: 25–31%
- Obese: 32%+
Pros and Limitations
Why people like it
- No special equipment required
- Fast and inexpensive
- Useful for trend tracking over time
What to keep in mind
- Small measuring errors can change results
- Very muscular or atypical body shapes may be misestimated
- It is an estimate, not a clinical diagnosis
Best Practice for Tracking Progress
Use this calculator under similar conditions each time: same time of day, same hydration status, and same tape position. If your body fat trend is moving in the right direction over several weeks, that trend is often more important than a single reading.
Pair body fat tracking with performance metrics like strength, endurance, sleep quality, and energy levels for a fuller health picture.
Frequently Asked Questions
Is Navy body fat more accurate than BMI?
For body composition, usually yes. BMI is a broad screening tool and does not directly estimate fat percentage.
Can I use centimeters?
Yes. This calculator accepts both inches and centimeters.
How often should I measure?
Once every 1–2 weeks is enough for most people, unless advised otherwise by a coach or clinician.
Bottom Line
The Navy method body fat calculator is a practical way to estimate and monitor body fat without specialized tools. Use it consistently, focus on long-term trends, and combine it with healthy nutrition, resistance training, and good recovery habits.