What is BMI?

What is BMI?

Studies have shown that weight is a pretty good predictor of overall health. The heavier you are, the more at risk you become for conditions such as heart disease, diabetes and strokes. It is therefore in your interest to stay within a normal weight range.


The Body Mass Index (BMI) is a tool that allows anyone to quickly figure out their healthy weight range using their weight and height. BMI is simply a ratio between weight and height. The taller you are, the heavier you can be and still fit into a ‘normal’ weight category.

Calculate BMI

To figure out your BMI, take your weight in pounds and divide it by your height in inches squared and multiply the result by 703. If you weigh 170 pounds and are 5 feet 10 inches, you would convert your height into inches (5 feet 10 inches = 70 inches), square it (70 inches x 70 inches = 4900) and divide your weight into that number (160 divided by 4900 = 0.033). Take your result and multiply it by 703 (0.033 x 703 = 23.2). The result is your BMI. (BMI Calculator)

Weight Category

Once you have a number that represents your BMI, find out where it fits into the table below to figure out if you’re underweight, normal, overweight or obese. Should you be worried about your BMI? It depends on where you fall. If you’re on the borderline of being overweight, there’s probably not a big reason to worry. If you fall into any of the obese categories, you need to fix your weight.

When interpreting your BMI, make sure you realize that BMI is blind. It doesn’t differentiate between muscle weight, fat weight or big and small frames. You need to figure that out on your own. You should ask yourself a few questions. Am I overweight because I’m muscular or because I’m fat? Am I overweight because I have a bigger frame than the average person?

Healthy Weight Range

BMI can give you a good idea of your healthy weight range but it isn’t the only tool you should use. A more accurate way to figure that out is to test your body fat percentage. If you’re within a normal body fat percentage but overweight according to your BMI, there’s less of a reason to worry. If however, you’re overweight in both tests, you need to make a change in your lifestyle.

If you’re not good at math, use the BMI Calculator or the healthy weight range calculator.

Your BMI Weight Category
18.5 and Under Underweight
18.6-24.9 Normal
25-29.9 Overweight
30-34.9 Obese Class 1
35-39.9 Obese Class 2
40 and Over Obese Class 3

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