BMI Calculator

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The Body Mass Index (BMI) Calculator can be used to calculate BMI value and corresponding weight status while taking age into consideration. Use the "Metric Units" tab for the International System of Units or the "Other Units" tab to convert units into either US or metric units. Note that the calculator also computes the Ponderal Index in addition to BMI, both of which are discussed below in detail.

BMI is a measurement of a person's leanness or corpulence based on their height and weight, and is intended to quantify tissue mass. It is widely used as a general indicator of whether a person has a healthy body weight for their height. Specifically, the value obtained from the calculation of BMI is used to categorize whether a person is underweight, normal weight, overweight, or obese depending on what range the value falls between. These ranges of BMI vary based on factors such as region and age, and are sometimes further divided into subcategories such as severely underweight or very severely obese. Being overweight or underweight can have significant health effects, so while BMI is an imperfect measure of healthy body weight, it is a useful indicator of whether any additional testing or action is required. Refer to the table below to see the different categories based on BMI that is used by the calculator.

This calculator computes the body mass index and rates it appropriately for men, women, children, juveniles and seniors. The SBMI – an index that has been developed four years ago especially for this calculator – serves for this purpose. It is based on the results of the most comprehensive study* published so far on the BMI and its associated health risks.

There's no "perfect weight" that fits everyone. BMI, or body mass index, measures how healthy your weight is based on how tall you are. It gives you a clue to your risk for weight-related health problems.

BMI or body mass index is a measure of how much body mass an individual has according to his weight and height. To calculate your BMI, simply divide your weight in kilograms by your height squared in metres. You can also find the results instantly by entering the height and weight data in online BMI calculators. BMI is not always an appropriate indicator of a person's health. Growing children and elderly people may have less muscle mass and therefore lower weight, thus lowering their BMI. On the other hand, athletes may have higher BMI as they put on plenty of muscle from exercise.

How is BMI measured?

The BMI formula is quantified as kg/m2 for most adults, irrespective of gender. The formula that uses kilograms and meters is called a metric BMI formula while the one that uses pounds and inches for measurement is called the imperial BMI formula. The BMI score chart is applied to adults aged 20 and above. A BMI between 18.5 and 25 is considered normal, between 25 and 30 overweight, between 30 to 35 fat, and between 35 and 40 too fat. BMI should preferably be measured first thing in the morning before breakfast, the time when your weight is most accurate.

What is ideal BMI for a man?

Maintaining a healthy body weight is important for everyone. According to the Center for Disease Control, men who have a BMI of 30 and above are obese, between 18.5 and 25 are considered normal, those with BMI below 18.5 are labelled underweight and those with BMI between 25 and 29 are considered overweight. As a thumb rule, taller men should weigh more than shorter guys, generally 2 to 4 points more per inch of height. The tendency to put on weight also increases with age, even though height, body frame and gender play crucial roles in determining your BMI levels.

What is ideal BMI for a woman?

The ideal, overweight, underweight and obese BMI ranges for men and women are the same with only minor differences. A National Institute for Health, USA study found that women who had never smoked but were overweight had a 13 per cent increased chance of dying, than those with a BMI between 22.5 and 24.9. Women who are obese or severely obese had significantly higher chances of dying early. Researchers saw a 44 per cent rise in risk of death for participants with BMI of 30 to 35 and an 88 per cent upside in risk for those with a BMI of 35 to 40, followed by a 250 per cent higher risk of dying for women whose BMIs fell between 40 and 49.

The BMI calculator is a useful tool that measures whether you are overweight, underweight, or just right. Your weight alone is not enough to tell, as a tall, skinny man may easily weigh more than a short but rotund woman. The body mass index, or BMI, overcomes this problem by finding a ratio of your weight to your height, and returning a single number. This number will fit into a category on the scale of BMI ranges, which are defined as underweight, normal, overweight, and obese.

How to calculate BMI

First, let's cover the calculation:

So the body mass index formula is as follows:

BMI = weight / height².

Normal BMI

Our BMI calculator makes it a piece of cake for you to find your number. However, please remember that BMI is a rough estimation. The result can be somewhat misleading for individuals who are well muscled (such as body builders), or for those who have lost a significant amount of muscle (such as the elderly).

If you are unsure whether or not you fall within the "normal" range of muscle mass, please consider using one of our more specialized calculators. The body fat calculator can zero-in on your percentage of body fat, while mass calculator can tell you how much you would weigh without any fat.

BMI ranges

There are five basic ranges within the BMI scale:

Underweight = less than 18.5

Normal weight = 18.5 - 24.9

Overweight = 25 - 29.9

Obesity = 30 - 35

Severe obesity = 35 and more

The BMI Prime is a nifty modification to our own BMI calculator. It's a decimal number where 1.0 = the upper limit to the "normal BMI" range. It's a super easy way to see if you're overweight or not. If your BMI Prime is more than 1, then you've got some weight to lose.

Using body mass index calculator

At the top of our BMI calculator are fields for you to plug in your height and weight. Plug in these values, and you'll instantly have your BMI, your BMI Prime (see above) and a little message telling you what range you fall into.

If you're overweight and want to know exactly how much you'll have to lose to get into the healthy range, you can do that too. Leave your height and weight in the boxes where they are, and type "0.9" into the BMI Prime box. Your weight and BMI will adjust themselves.