BMI Calculator: What Your Number Really Means
BMI is the quickest way to check whether your weight is in a typical range for your height. Here is how the number is worked out and what to do with it.
What is the BMI Calculator?
This tool divides your weight in kilograms by your height in metres squared to give your Body Mass Index (BMI), then places the result in a standard category: underweight, healthy, overweight, or obese. It also shows the weight range that would put you in the healthy band for your height. The result is general information only, not medical advice, and BMI does not account for muscle mass, age, or body composition.
How to use it
- Enter your weight in kilograms.
- Enter your height in centimetres.
- Read your BMI, category, and healthy weight range.
Worked example
A person weighing 70 kg at 175 cm tall has a BMI of 22.86, which falls in the healthy range. Their healthy weight range for that height is 56.66 kg to 76.26 kg.
What BMI is considered healthy?
A BMI between 18.5 and 24.9 is generally considered the healthy range for most adults. Below 18.5 is classed as underweight, 25 to 29.9 as overweight, and 30 or above as obese. These bands are screening guides rather than diagnoses, so treat any result as a starting point for a conversation with a health professional, not a verdict on your health.
Frequently asked questions
What is a healthy BMI?
A BMI from 18.5 to 24.9 is generally classed as the healthy range, but it is only a rough guide and does not suit every body type.
Does BMI work for athletes?
Not always — a very muscular person can have a high BMI without excess body fat, because BMI cannot tell muscle apart from fat.