How to use this calculator
- Enter or choose units.
- The your BMI updates as you type. Use Copy result or Share to keep it.
Formula
BMI = weight (kg) ÷ height (m)²; in US units: BMI = 703 × weight (lb) ÷ height (in)²
- weight
- body weight
- height
- standing height
Worked example
- Height = 175 cm = 1.75 m, so height² = 3.0625.
- BMI = 70 ÷ 3.0625 = 22.86, shown as 22.9.
- A healthy range at 1.75 m is 18.5 × 3.0625 to 24.9 × 3.0625 ≈ 56.7–76.3 kg.
A 70 kg adult who is 175 cm tall has a BMI of 22.9, in the healthy weight range.
What the result means
BMI is a quick screening measure for adult populations, not a diagnosis. It does not distinguish muscle from fat, so very muscular people can score as overweight. Some health bodies recommend lower cut-off points for people of South Asian, Chinese and other Asian backgrounds.
Assumptions and limits
- Adult (18 or older); children and teenagers need age- and sex-specific BMI percentiles.
- WHO adult categories: under 18.5 underweight, 18.5–24.9 healthy, 25–29.9 overweight, 30 and above obesity.
- Not suitable during pregnancy.
- Does not measure body fat, its distribution, or fitness.
Questions
Is BMI accurate?
It correlates with body fat across populations but can misclassify individuals, particularly athletes, older adults and people with different body compositions. Waist measurement adds useful information.
Does BMI differ for men and women?
The adult formula and categories are the same for everyone. Children’s BMI is interpreted using sex-specific growth charts.
Sources
Please note: This is a general screening estimate for adults, not medical advice or a diagnosis. Talk to a qualified health professional about your health.