BMI Prime Calculator

The BMI calculator is a handy way to find out if you are overweight, underweight, or just right. Your weight alone is not enough to determine this, as a tall, skinny man can easily weigh more than a short, but curvy woman. The body mass index, or BMI, solves this problem by calculating the ratio of your weight to your height and giving a single number.

BMI Categories

This number corresponds to a category on the BMI scale, which are defined as follows:

• Underweight
• Normal weight
• Overweight
• Obese
• Severely obese

How to Calculate BMI?

Steps to Calculate BMI:

1. Divide your weight (in kilograms) by your height (in meters).
2. Divide the result by your height to get your BMI.

Formula: BMI = weight / height²

Normal BMI

Our BMI calculator allows you to find your BMI in the blink of an eye. However, keep in mind that BMI is a rough estimate. The result can be somewhat misleading for people with a lot of muscle (such as bodybuilders) or for those who have lost a lot of muscle (such as older people).

What Are the BMI Categories?

The BMI scale has five basic categories:

• Underweight: less than 18.5
• Normal weight: 18.5 to 24.9
• Overweight: 25 to 29.9
• Obese: 30 to 35
• Severely obese: 35 and above

BMI Prime

The BMI prime is a nice twist on our own BMI calculator. It is a decimal number where 1.0 = the upper limit of the “normal BMI” range. It is a very simple way to determine whether or not you are overweight. If your BMI prime is greater than 1, you have weight to lose.

Using Our BMI Calculator

At the top of our BMI calculator, there are fields for you to enter your height and weight. Enter these values and you will instantly get your BMI, your BMI prime (see above), and a little message telling you what range you are in.

Tip for Adjustments

If the height field adjusts itself when you change other fields, you should lock it. Click to the right of the field and select the lock icon (Autosave) to keep this number in place while you change the values in the other fields. Unless you are planning to grow!

Learn More

Basal Metabolic Rate

If you want to know if your metabolism is on your side in your quest for a healthy weight, try our Basal Metabolic Rate Calculator. Your basal metabolic rate is the level of activity of your body’s metabolism when you wake up in the morning. This is the most reliable time of day to measure metabolism, because you are not yet active!

Ideal Weight

Now that you know how to calculate BMI, the next number to know is your ideal weight. Use our ideal weight calculator to determine it in a snap. You can also use our daily energy requirement calculator to calculate the number of calories your body needs to maintain your current weight.

FAQ

Does Normal BMI Depend on Age?

No for adults. The normal BMI range is between 18.5 and 24.9, and it does not depend on the person’s age. However, for children, age is essential in assessing their weight.

What Is the BMI of a 75 kg Man?

The answer depends on the height! Let’s say it is 180 cm. The BMI is then:

BMI = weight / height²

Where the weight must be expressed in kilograms and the height in meters.

Convert height into meters: 180 / 100 = 1.8 m.

Calculate: weight / height² = 75 / 1.8² = 23.148.