BMI body mass index formula in a notepad.
BMI Calculator

Find out your BMI, and what it means, with our easy calculator.

BMI Calculator

Choose your measurement preference then enter your height and weight to calculate your BMI

Height m
Weight kg
Height ft in
Weight st lb
Height ft in
Weight lb

What is BMI?

BMI stands for body mass index which is a formula which relates Body Weight to height. This enables people to determine whether they are at a weight which is healthy for them.

What Your BMI Calculation Means

Under 18.5* Underweight
18.5* - 25 Healthy Weight
25 - 30 Overweight
30 - 40 Obese
Over 40 Severely obese

* There are two different ranges for healthy BMI put forward by different, but respected, sources. The British Nutrition Foundation, for example, gives 20-25 as healthy range and less than 20 as underweight. The Food Standards Agency's BMI calculator gives 18.5-25 as healthy and less than 18.5 as underweight. Cancer Research UK gives both ranges in different sections of its website. It seems that we can be a bit relaxed about a BMI of between 18.5 and 20, and not start worrying about being underweight unless BMI is less than 18.5. 

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