Body Fat Calculator
Calculate your body fat percentage using two proven methods — the US Navy circumference method and the BMI-based method — with your fat mass, lean mass, and fitness category.
Units & Profile
Body Measurements
How to Use the Body Fat Calculator
- 1
Select your unit system and enter your basic information including gender and age. Gender is required because men and women have different body fat distribution and the formulas use gender-specific equations.
- 2
Measure your neck circumference just below the Adam's apple keeping the tape horizontal. For waist measure at the navel for men or the narrowest point for women. Women also need to measure hips at the widest point.
- 3
The calculator uses the US Navy circumference method as the primary result as it is the most accurate non-invasive body fat estimation method available without equipment. The BMI-based method is shown for comparison.
- 4
Click Calculate to see your body fat percentage, fat mass, lean mass, and body fat category. Download the free PDF to track changes over time as you progress toward your fitness goals.
Example Calculation
Male | Age 35 | Weight 180 lbs | Height 70 in | Neck 15 in | Waist 34 in
- Navy Body Fat: 17.5%
- BMI-Based Body Fat: 22.8%
- Category: Fitness
- Fat Mass: 31.5 lbs
- Lean Mass: 148.5 lbs
- BMI: 25.8
Frequently Asked Questions
What is a healthy body fat percentage?
Healthy body fat ranges differ between men and women. For men the athletic range is 6 to 13% the fitness range is 14 to 17% and the average healthy range is 18 to 24%. For women the athletic range is 14 to 20% the fitness range is 21 to 24% and the average healthy range is 25 to 31%. Essential fat — the minimum needed for bodily functions — is 2 to 5% for men and 10 to 13% for women. Body fat below essential levels is dangerous and medically concerning.
How does the US Navy body fat method work?
The US Navy method estimates body fat percentage using circumference measurements. For men it uses neck and waist measurements along with height. For women it uses neck waist and hip measurements along with height. The formula applies logarithmic calculations to these measurements to estimate body fat. This method was developed by the US Navy for use without expensive equipment and is considered one of the most accurate non-invasive methods available with an error margin of approximately 3 to 4 percentage points.
Why is body fat percentage more useful than BMI?
BMI only measures weight relative to height and cannot distinguish between muscle and fat. A muscular athlete and an obese sedentary person of the same height and weight would have identical BMIs but vastly different health profiles. Body fat percentage directly measures fat as a proportion of total body weight giving a more accurate picture of body composition and health. However body fat measurement also has limitations and should be used alongside other health metrics.
How do I measure my waist and neck accurately?
For neck measurement stand upright and measure around your neck just below the Adam's apple keeping the measuring tape horizontal. Do not pull the tape tight — it should lie flat against the skin. For waist measurement men should measure at the level of the navel while relaxed not held in. Women should measure at the narrowest point between the ribs and hips. Take measurements in the morning before eating for the most consistent results.
How can I reduce my body fat percentage?
Reducing body fat requires a combination of caloric deficit and physical activity. Cardiovascular exercise burns calories and fat while strength training builds muscle which increases your resting metabolism. Aim to lose 0.5 to 1% body fat per month which is sustainable without significant muscle loss. Tracking both body weight and body fat percentage is more informative than tracking weight alone since muscle gain can offset fat loss on the scale while body composition is actually improving.
Disclaimer: This report is generated for informational purposes only. TheCalcTool is not a licensed medical professional. Body fat percentage calculations are estimates. The US Navy method has an error margin of approximately 3 to 4 percentage points. Results may be less accurate for very muscular individuals elderly people or those with unusual body proportions. For precise body composition measurement consult a healthcare professional who can perform DEXA scan hydrostatic weighing or other clinical methods.