BMI Calculator

Calculate your Body Mass Index (BMI) and see your category: underweight, normal, overweight or obese. Free.

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How to calculate BMI

Body Mass Index (BMI) relates your weight to your height. It is calculated by dividing weight in kilograms by height in meters squared. It is a quick, simple indicator of whether your weight is in a healthy range.

The BMI formula

BMI = Weight (kg) ÷ Height (m)²

For example, a person weighing 70 kg at 1.75 m has a BMI of 70 ÷ (1.75 × 1.75) = 22.9, which is within the normal range.

BMI categories

Below 18.5 is underweight; between 18.5 and 24.9 is normal weight; between 25 and 29.9 is overweight; and 30 or more is obesity.

Limitations

BMI does not distinguish between muscle and fat. Very muscular people can have a high BMI without being less healthy. It is a guideline, not a diagnosis: consult a health professional.

Frequently Asked Questions

What is BMI?
Body Mass Index relates your weight and height: it is calculated by dividing weight in kg by height in meters squared.
What is a normal BMI?
A BMI between 18.5 and 24.9 is considered normal. Below 18.5 is underweight, 25-29.9 overweight, and 30 or more is obesity.
Is BMI reliable?
It is a quick, useful reference for most adults, though it does not distinguish between muscle and fat. For a full assessment, consult a professional.

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