Calorie Intake Calculator

BMI calculator

Calculate your body mass index and the healthy weight range for your height, with WHO or Asian cut-offs.

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Cut-offs

What is BMI?

Body mass index compares your weight with your height. It is quick, free and useful for spotting risk across large groups of people.

BMI = weight (kg) ÷ height (m)²
US units: BMI = 703 × weight (lb) ÷ height (in)²

BMI categories

CategoryWHOAsian cut-offs
UnderweightBelow 18.5Below 18.5
Healthy weight18.5–24.918.5–22.9
Overweight25.0–29.923.0–27.4
Obesity30 and above27.5 and above

People of South Asian, Chinese and other Asian backgrounds tend to have higher health risks at a lower BMI. That is why the WHO and bodies such as India’s health ministry and the UK’s NICE recommend lower thresholds for these groups.

What BMI does not tell you

BMI cannot tell muscle from fat, so very muscular people can show as overweight. It also says nothing about where fat is stored. Waist size adds useful information: a waist under half your height is a good general target.

BMI is designed for adults. Children and teenagers use age- and sex-specific charts, so this calculator is not suitable for them.

Frequently asked questions

What is a healthy BMI?
For most adults, 18.5 to 24.9. For people of Asian background, 18.5 to 22.9 is often used.
Is BMI accurate?
It is a reasonable screening measure for most people, but it misreads very muscular people and older adults who have lost muscle. Combine it with waist size and advice from a doctor.
What is BMI Prime?
BMI Prime is your BMI divided by 25, the upper limit of the healthy range. A value of 1.00 sits right at that limit.

Reviewed and updated 22 October 2026. See how we calculate.