It’s not enough to step on a scale and know if you’re at the correct weight, underweight, or overweight. Your height plays a part in the process too, and that’s why you will require a **body mass index (BMI) calculator** to help determine your BMI range.
The **BMI calculator** will compare your weight to your height to provide a number. You then compare this number to the ratings of a healthy BMI to see whether you’re “normal” or something else.
Below, you can learn how to calculate BMI, what a healthy BMI range is, and what the various categories are.

The calculation is straightforward.
Divide your kilogram weight by your meter height.
Divide the answer by your total height to get your BMI.
**The formula for your BMI looks like this:**
*BMI = weight / height²*

It’s important to understand that using a **BMI calculator** only provides you with a rough estimate of your body mass index. Such a straightforward calculation doesn’t consider your muscle tone or lack thereof.
If you require a more accurate analysis of your body weight health, then you can use body fat calculators or even lean body mass calculators to determine your body fat percentage and your weight should you lose your fat.

When you score your body mass index, they fall into the following five categories:
**Underweight:** Less than 18.5
**Normal:** 18.5 to 24.9
**Overweight:** 25 to 29.9
**Obese:** 30 to 35
**Severe Obesity:** 35 and over
This **BMI calculator** also includes a modification known as BMI prime. With this modification, 1.0 is equal to the upper limit of what you consider a healthy BMI range. In essence, if your BMI Prime is higher than one, you should consider losing weight.

The calculator includes an area for you to input your height and weight data. Once you add that information, the **body mass index calculator** immediately offers an answer. You can be underweight, normal, overweight, obese, or severely obese. You can then play with the weight category to determine how much you need to lose to fit within the healthy weight range.

There is more to being healthy than relying on what a **BMI calculator** tells you. You can also use a **basal metabolic rate calculator** to determine if your metabolism is helping you to lose weight or whether you need to make more of an effort to eat regularly and often.