Health and Fitness / Free Tools
Free Body Fat Percentage Calculator Online
Use this free body fat percentage calculator to estimate your body fat using the U.S. Navy circumference method. It works as a general body composition calculator for men and women, using just a few tape measurements - no scale, no sign-up, and no special equipment required.
What is a body fat percentage calculator and why it matters
A body fat percentage calculator estimates how much of your body weight comes from fat versus lean mass (muscle, bone, organs, and water). This matters because body fat percentage is a more meaningful health and fitness indicator than weight or BMI alone, since it doesn't distinguish between muscle and fat. This calculator uses the U.S. Navy circumference method, a widely used estimation formula that only requires a tape measure - no calipers, scales, or scans needed.
How this calculator works
The Navy method estimates body fat using the circumference of the neck and waist (and hips for women), combined with height. These measurements are plugged into a logarithmic formula validated against more precise methods like hydrostatic weighing. It is not as accurate as DEXA scans or skinfold calipers used by professionals, but it offers a solid estimate for tracking progress over time using consistent measurements.
Common searches this calculator answers
- What is my body fat percentage?
- How do I calculate body fat with a tape measure?
- What is a healthy body fat percentage for my age and gender?
- How much fat mass and lean mass do I have?
- Is my body fat percentage in the athletic or fitness range?
How to use it
- Select your gender and preferred measurement units.
- Enter your height.
- Measure and enter your neck circumference, just below the larynx.
- Measure and enter your waist circumference at the navel (women also enter hip circumference at the widest point).
- Optionally enter your body weight to see estimated fat mass and lean mass.
- Click Calculate body fat to see your result and category.
Tips
- Measure with a flexible tape measure, snug but not compressing the skin, for the most consistent results.
- Take measurements at the same time of day, ideally in the morning before eating, for consistency between check-ins.
- This method gives an estimate, not a clinical measurement - use it to track trends over weeks and months rather than a single precise reading.
- Body fat percentage naturally varies by age and gender, so compare your result to the appropriate category range rather than a single universal target.
Body fat category ranges (reference)
| Category | Women | Men |
|---|---|---|
| Essential fat | 10-13% | 2-5% |
| Athletes | 14-20% | 6-13% |
| Fitness | 21-24% | 14-17% |
| Average | 25-31% | 18-24% |
| Obese | 32%+ | 25%+ |
Frequently asked questions
Is this body fat percentage calculator free to use?
Yes. It is completely free, works in your browser, and does not require any sign-up or download.
How accurate is the U.S. Navy method?
It is generally accurate within a few percentage points for most body types, though it can be less precise for people with unusual body compositions, such as very muscular or very lean individuals.
Why does the calculator ask for hip measurement only for women?
The Navy formula uses different variables for men and women. Men's estimates rely on neck and waist measurements, while women's estimates also factor in hip circumference for better accuracy.
Can I use centimeters instead of inches?
Yes. Use the units dropdown to switch between inches and centimeters before entering your measurements.
What is fat mass and lean mass?
Fat mass is the portion of your body weight made up of fat, while lean mass includes muscle, bone, organs, and water. Enter your body weight to see both broken out in pounds or kilograms.