How to use the Body Fat Calculator
Enter the height, neck circumference, waist circumference, hip circumference and body weight and the result appears straight away. Everything runs in your browser, so nothing you type is uploaded.
How it works
Navy method (log10 of circumference measurements)
Examples
- Man: 178 cm, neck 38 cm, waist 85 cm
Body fat: 16.4% Category (American Council on Exercise ranges): Fitness Fat mass: 12.8 kg; lean mass: 65.2 kg
- Man: 178 cm, neck 38 cm, waist 95 cm
Body fat: 23.6% Category (American Council on Exercise ranges): Average Fat mass: 20.7 kg; lean mass: 67.3 kg
- Woman: 165 cm, neck 32 cm, waist 74 cm, hip 98 cm
Body fat: 28.4% Category (American Council on Exercise ranges): Average Fat mass: 18.2 kg; lean mass: 45.8 kg
Limitations and assumptions
Navy estimates can be several points off, especially for very lean or very muscular people. DEXA scans are more accurate. General estimate for adults, not medical advice. Speak to a doctor or registered dietitian before making significant changes to diet, exercise or health routines.
Frequently asked questions
How accurate is the Navy body fat formula?
It is an estimate that is typically within a few percentage points for most people. DEXA scans and other lab methods are more accurate.
Where do I measure?
Neck just below the larynx, waist at the navel for men and at the narrowest point for women, and hips at the widest point. Keep the tape snug but not tight.
What is a healthy body fat percentage?
Ranges vary by age and sex; the tool labels results with American Council on Exercise ranges, for example Fitness is about 14 to 17 percent for men and 21 to 24 percent for women. Healthy ranges also vary with age.
Should I use this to diagnose anything?
No. It is a general estimate, not a medical assessment.