About this calculator
Measure your neck and waist (and hips for women), and enter them with your height and weight.
How to use it
- Choose your sex and enter height and weight.
- Measure your neck below the larynx and your waist.
- Women also measure the widest part of the hips.
The formula
Men: 495 ÷ (1.0324 − 0.19077 log(waist − neck) + 0.15456 log(height)) − 450
- women
- 495 ÷ (1.29579 − 0.35004 log(waist + hip − neck) + 0.221 log(height)) − 450
- measurements
- in centimetres; log is base 10
Worked example
A man 170 cm, 68 kg, neck 38 cm, waist 85 cm
- Body fat = 17.8%.
- Fat mass = 12.1 kg; lean mass = 55.9 kg.
- That falls in the “fit” range for men.
What the result means
Track the trend over weeks rather than a single reading; tape measurements vary.
Assumptions
- Measured on bare skin, relaxed, not after a meal.
Limitations
- Usually within 3 to 4 percentage points of lab methods.
- Less accurate for very lean or very muscular people.
Frequently asked questions
What is a healthy body fat percentage?
Roughly 14% to 24% for men and 21% to 31% for women is typical for fit to average adults.
Where do I measure my waist?
Men at the navel; women at the narrowest point between ribs and hips.
Is this as accurate as a DEXA scan?
No, but it is free and good for tracking change over time.
Not medical advice. This calculator is a general screening tool and cannot diagnose any condition. Results are estimates. Please talk to a doctor or a qualified health professional about your health and before making changes to diet, exercise or treatment.
Last reviewed on 1 October 2026. Found a mistake? Tell us.