Calculators
Body Fat Calculator
Estimate body fat percentage, fat mass, lean mass, and category using the Navy method or a BMI-based fallback estimate.
Athletic range, using Navy method
Consult a doctor or nutritionist for personalized advice.
How the Navy method works
The Navy method estimates body fat from circumference measurements. Men use height, neck, and waist. Women use height, neck, waist, and hips. The calculator converts imperial entries to centimeters, then applies the formulas below.
Men: %BF = 495 / (1.0324 - 0.19077log10(waist - neck) + 0.15456log10(height)) - 450Women: %BF = 495 / (1.29579 - 0.35004log10(waist + hips - neck) + 0.22100log10(height)) - 450Weight is not part of the Navy percentage formula, but it is needed to estimate fat mass and lean mass. Fat mass is body weight multiplied by body fat percentage.
Example reference table
General adult body fat categories. These ranges are common references, not medical cutoffs.
| Category | Men | Women |
|---|---|---|
| Essential fat | 2 to 5% | 10 to 13% |
| Athletes | 6 to 13% | 14 to 20% |
| Fitness | 14 to 17% | 21 to 24% |
| Average | 18 to 24% | 25 to 31% |
| High | 25% and above | 32% and above |
Frequently asked questions
How accurate is the Navy body fat method?
The Navy method is a practical estimate based on tape measurements. It is useful for tracking trends, but it is not as precise as DEXA, hydrostatic weighing, or a trained clinical assessment.
What is a healthy body fat range?
Healthy ranges vary by age, sex, training status, and medical history. Many adult men fall in a healthy range around 10 to 24%, while many adult women fall around 18 to 31%, but personal context matters.
How should I measure my waist, neck, and hips?
Use a flexible tape, keep it level, and measure relaxed without pulling the tape tight. Measure the neck below the Adam's apple, the waist around the navel, and hips at the widest point.
Why do women need a hip measurement?
The Navy formula for women uses waist, hips, neck, and height because fat distribution differs by sex. The hip measurement helps the estimate account for that distribution.
When should I use the BMI estimate?
Use the BMI method when you do not have tape measurements. It is less personal than the Navy method because it only uses age, sex, height, and weight, so treat it as a fallback estimate.