Body Fat Calculator
Estimate your body fat percentage using the U.S. Navy method.
Body Measurements
Measure at the smallest point below the larynx
Measure at navel level (or widest point for women)
Body Fat Percentage
12.9%
Athlete
About This Calculator
The Body Fat Calculator estimates your body fat percentage using the U.S. Navy method, which uses body measurements (neck, waist, and hip circumference) along with height, weight, age, and gender to calculate body composition.
Body fat percentage is a better indicator of health than BMI alone, as it distinguishes between muscle mass and fat. The Navy method is widely used and provides a reasonable estimate without specialized equipment.
Formula & Calculation Method
U.S. Navy Body Fat Formula:
For Men:
BF% = 495 / (1.0324 - 0.19077 × log₁₀(waist - neck) + 0.15456 × log₁₀(height)) - 450
For Women:
BF% = 495 / (1.29579 - 0.35004 × log₁₀(waist + hip - neck) + 0.22100 × log₁₀(height)) - 450
All measurements should be in centimeters (or inches, which are converted). Measurements should be taken when standing straight, with tape measure parallel to the floor. The calculator uses logarithmic functions to estimate body fat percentage based on body circumference ratios.
How to Use This Calculator
- Select Gender: Choose your biological sex (affects the formula used).
- Enter Age: Input your age in years.
- Select Unit: Choose metric (kg/cm) or imperial (lb/in) measurements.
- Enter Weight: Input your current body weight.
- Enter Height: Input your height (standing straight).
- Measure Neck: Measure neck circumference at the smallest point (below the larynx).
- Measure Waist: Measure waist at the navel level (or widest point for women).
- Measure Hip (Women only): Measure hip at the widest point (for women).
- View Results: See your body fat percentage and category classification.
Frequently Asked Questions
How accurate is the Navy body fat calculator?
The Navy method provides a reasonable estimate (±3-4%) for most people but may be less accurate for very lean or very obese individuals. For precise measurements, consider DEXA scans or hydrostatic weighing.
When should I take measurements?
Take measurements in the morning before eating or drinking, and ensure the tape measure is level and snug but not compressing skin. Measure at the same time of day for consistency.
What is a healthy body fat percentage?
For men: Essential fat 2-5%, Athlete 6-13%, Fitness 14-17%, Average 18-24%, Obese 25%+. For women: Essential fat 10-13%, Athlete 14-20%, Fitness 21-24%, Average 25-31%, Obese 32%+.
Why is hip measurement needed for women?
Women naturally store more fat in the hip and thigh area. Including hip measurement in the formula provides a more accurate body fat estimate for female bodies.
Expert Reviewed
This calculator was reviewed by NumCalculators Editorial Team, Multi-disciplinary Expert Team