BMI Definition Our free online BMI calculator makes it easy for anyone to calculate BMI with just a few keystrokes. Enter in your height and weight and press the calculate BMI button – that’s all there is to it! Calculating Body Mass Index is useful for determining the amount of body fat that you may have. Get started learning how to calculate BMI right now and then be sure to use all of our other health calculators!

Below 18.5

Underweight

18.5 – 24.9

Normal

25.0 – 29.9

Overweight

30.0 and Above

Obese

How to Calculate BMI Let's be honest - sometimes the best bmi calculator is the one that is easy to use and doesn't require us to even know what the bmi formula is in the first place! But if you want to know the exact formula for calculating bmi then please check out the "Formula" box above.