Body Fat Calculator – Understand Your True Body Composition
Calculate your body fat percentage, fat mass, and lean mass using the US Navy Method.
Body weight alone does not tell the full story of your health. Two people with the same weight can have very different body compositions. This Body Fat Calculator estimates your body fat percentage, fat mass, and lean mass using the widely recognized US Navy Method.
This method focuses on body measurements rather than scale weight, providing a clearer picture of what your body is actually made of.
This calculator is designed for educational and informational purposes only and follows established body composition standards.
Measurements (US Navy Method)
Body Fat Percentage
...
What Is Body Fat Percentage?
Body fat percentage represents the proportion of your total body weight that comes from fat tissue. Your body weight consists of fat mass (essential and stored body fat) and lean mass (muscles, bones, organs, and water).
Your body weight consists of:
- Fat mass – essential and stored body fat
- Lean mass – muscles, bones, organs, and water
Understanding body fat percentage is often more useful than weight alone when assessing fitness and health.
What Is the US Navy Body Fat Method?
The US Navy Method is a circumference-based formula developed for military fitness assessments. It estimates body fat percentage using simple body measurements rather than expensive equipment.
Measurements Used:
- Height
- Neck circumference
- Waist circumference
- Hip circumference (for females)
This method is popular because it is:
- Simple and fast
- Non-invasive
- Equipment-free
- Practical for large populations
How This Body Fat Calculator Works
All calculations run locally in your browser.
How to Use This Body Fat Calculator
Using this calculator is simple and requires no registration.
Step 1: Select Gender
Different formulas are used for males and females.
Step 2: Enter Height
Enter your height in centimeters.
Step 3: Enter Weight
Provide your current body weight.
Step 4: Measure Neck Circumference
Measure around the narrowest part of your neck.
Step 5: Measure Waist Circumference
Measure at the level of your navel, relaxed, without pulling the tape tight.
Step 6: Calculate
Click Calculate Body Fat to see your results instantly.
Understanding Your Results
Body Fat Percentage
The estimated percentage of your total body weight that comes from fat.
Fat Mass
The estimated amount of fat tissue in your body.
Lean Mass
Everything that is not fat: muscle, bones, organs, and water.
These values provide a more meaningful health snapshot than weight alone.
Why Body Fat Is More Important Than BMI
BMI measures weight relative to height but does not distinguish between fat and muscle. Athletes and muscular individuals may have a high BMI but a healthy body fat percentage.
Body fat percentage:
Athletes and muscular individuals may have a high BMI but a healthy body fat percentage.
Accuracy of the US Navy Method
The US Navy method provides a reasonable estimate but is not perfect. Use results as estimates, not exact values.
Strengths:
- ✓Simple and accessible
- ✓No special equipment required
- ✓Consistent for trend tracking
Limitations:
- !Accuracy depends on measurement technique
- !Does not directly measure internal fat
- !Less precise than medical imaging methods
Use results as estimates, not exact values.
Tips for Accurate Measurements
Consistency improves accuracy over time.
Who Should Use This Calculator?
It is not intended for children or clinical diagnosis.
Accuracy Limitations
- Accuracy depends on measurement technique
- Does not directly measure internal fat
- Less precise than medical imaging methods
- Assumes average fat distribution
Professional assessment is recommended for clinical use.
The Math: US Navy Circumference Method
Developed by the Naval Health Research Center, this formula uses body geometry to estimate density.
Men
495 / (1.0324 - 0.19077(log10(Waist - Neck)) + 0.15456(log10(Height))) - 450Women
495 / (1.29579 - 0.35004(log10(Waist + Hip - Neck)) + 0.22100(log10(Height))) - 450*Waist, Neck, and Hip in cm. Height in cm.
ExPro Athlete (Male)
- Height: 180 cm
- Neck: 40 cm
- Waist: 80 cm
Result: ~10.4% (Athlete Category)
Body Composition Reference Table
Common body fat profiles and categories based on standard benchmarks.
| Profile | Gender | Body Fat % | Category | Metabolic State |
|---|---|---|---|---|
| Pro Athlete | Male | 6-10% | Athlete | High performance |
| Endurance Runner | Female | 14-18% | Athlete | Optimal conditioning |
| Fitness Enthusiast | Male | 12-15% | Fitness | Visible definition |
| Active Professional | Female | 21-24% | Fitness | Healthy muscle tone |
| Average Adult | Male | 18-24% | Average | Normal health |
| Average Adult | Female | 25-31% | Average | Normal health |
| Overweight Baseline | Male | 25-29% | Overweight | Moderate health risk |
| Overweight Baseline | Female | 32-35% | Overweight | Moderate health risk |
| Sedentary Individual | Male | 30%+ | Obese | Increased health risk |
| Sedentary Individual | Female | 36%+ | Obese | Increased health risk |
| Body Recomp Phase | Male | 15-18% | Fitness | Improving metabolism |
| Body Recomp Phase | Female | 22-25% | Fitness | Improving metabolism |
| Elite Swimmer | Male | 10-12% | Athlete | Very low drag |
| Elite Swimmer | Female | 18-20% | Athlete | Optimal buoyancy |
| Powerlifter | Male | 20-25% | Average | High mass/power |
| Yoga Instructor | Female | 20-22% | Fitness | Functional lean mass |
| Weekend Warrior | Male | 16-20% | Fitness | Active lifestyle |
| New to Fitness | Female | 28-32% | Average | Weight loss target |
| Marathoner | Male | 8-12% | Athlete | Maximum efficiency |
| Health Seeker | Female | 24-28% | Average | Baseline well-being |
Body Fat Percentage Categories (Adults)
These ranges are general guidelines and may vary individually.
Related Tools
Popular Financial Tools
Frequently Asked Questions (FAQ)
What is body fat percentage?
Body fat percentage is the proportion of your total body weight that comes from fat tissue, as opposed to muscle, bone, organs, and water.
How does this body fat calculator work?
This calculator uses the US Navy Method, which estimates body fat percentage based on height and body circumference measurements such as the neck and waist.
Is the US Navy body fat method accurate?
The US Navy method provides a reasonable estimate for most adults. Accuracy depends on correct measurements and consistency.
Is body fat percentage better than BMI?
Body fat percentage often provides more insight than BMI because it distinguishes between fat mass and lean mass.
Does this calculator work for both men and women?
Yes. The calculator uses different equations for men and women to improve estimation accuracy.
How often should I measure my body fat?
Measuring every 2–4 weeks is usually sufficient to track meaningful changes over time.
Can body fat change without weight changing?
Yes. Fat loss and muscle gain can occur simultaneously, causing body composition changes even if body weight remains stable.
Does hydration affect body fat measurements?
Hydration levels can slightly influence measurements. For consistency, measure under similar conditions each time.
Is lower body fat always healthier?
Not necessarily. Extremely low body fat levels can also pose health risks, especially if maintained long term.
Is this calculator suitable for athletes?
Yes, but athletes with very high muscle mass may benefit from more advanced body composition testing methods.
Can this replace medical body fat testing?
No. This tool provides estimates for educational purposes and does not replace clinical assessments.
Does age affect body fat percentage?
Yes. Body fat distribution and healthy ranges can change with age.
Are body fat categories the same worldwide?
General categories are similar globally, but interpretations may vary by population and health guidelines.
Does this calculator store my personal data?
No. All calculations run locally in your browser, and no personal data is stored or shared.
What is the best time of day to measure body fat?
For consistency, measure at the same time of day, preferably in the morning before eating or exercising.
Can I use this calculator to track fitness progress?
Yes. Repeating measurements over time can help track trends in body composition.
Limitations of This Calculator
Results should be interpreted alongside other health indicators.
Educational Purpose Only (Important Disclaimer)
This Body Fat Calculator and its results are provided for educational and informational purposes only. They do not constitute medical advice, diagnosis, or treatment.
We are not healthcare providers or medical professionals. Body composition varies widely between individuals. Always consult a qualified healthcare professional for personalized health guidance.
Fact-Checked by:
ExpertToolkit Health Team
Last Updated:
January 2026