How do I measure BMI?

If you are wondering how to measure BMI, you can do so manually or you can use our free online BMI calculator. The final number indicates whether you are underweight, in a normal weight range, overweight or obese. The formula involves multiplying your weight in pounds by 703. Then divide it by your height squared. It might look like this for a man who is 5 foot 8 inches tall and weighs 180 pounds:

180 lbs. x 703/4624 (68×68 height in inches squared) =27.36 BMI

If you hate math, just use the handy BMI calculator provided on our home page. Since BMI is slightly different for different groups of people those variances are described below.

Measuring BMI for Women

Many women are concerned about their appearance and have body image issues. They may wonder what the BMI they have calculated for themselves really means. Calculating a BMI is a good way for a woman to get an idea of whether she should be concerned about her weight.

The scale is an arbitrary one, though, and a woman who is very muscular may have a BMI number that falls into the overweight category when she does not have a weight problem at all. The number may be a surprise to a woman who thinks she is too heavy if her score is in the normal range. In that case, hopefully she will be able to start to develop a more positive self-image that is not based on a number that happens to show up on a scale.

If the BMI measurement shows that a woman is overweight or obese, she can use this information as a springboard to making some positive changes in her life. Rather than go on a crash diet to lose weight, a better choice is to start by having a complete physical and discussing her weight loss plans with her doctor. Making small changes to her eating habits and getting more exercise can lead to a healthier weight and make it more likely that the woman will be able to maintain it over the long term.

Measuring BMI for Men

The same formula is used to calculate a BMI for men. This number is a screening tool that doctors and other health professionals use to get an indication of a man’s overall health. It is not meant to replace other screening methods used to determine a man’s health, though.

A man will still need to see his doctor for regular checkups, even if his BMI falls within the healthy weight range. A very athletic or muscular man may have a high BMI and be perfectly healthy. If there is concern about the number after the measurement has been made, the man can visit his doctor to make sure he is healthy and there are no underlying health conditions he needs to be concerned about.

Measuring BMI for Children

A BMI measurement can be used to determine whether a child is underweight, at a normal weight or overweight. It can be used starting when a child is two years old. Even if the number is higher than normal, the BMI alone can’t be used a diagnostic tool.

The child with a high BMI should be seen by a doctor to determine whether he or she really has an issue with excess body fat. A high reading is a sign that further investigation is needed, not an indication that the child in question should immediately be put on a restrictive diet. Other items, such as current diet, level of physical activity, family history and other health screenings should be conducted.

Measuring BMI for Teens

When a child moves into the teen years, the BMI can still be used, but the reading must be considered in light of the fact that body fat levels change during puberty. The amount of body fat is different for girls than it is for boys, and the BMI measurement alone may not reflect this fact.

Using the formula to calculate a BMI for a woman, man, child or adolescent can be used as a piece of the puzzle for determining the individual’s overall health. The number can indicate when a person should be considering going to see his or her doctor for further investigation, and a BMI measurement in the normal range should not be considered a substitution for getting regular checkups and any follow-up medical care recommended by a doctor.

If you really want to know what your BMI is, why don’t you use the free BMI calculator tool on this page? All you need to do is fill in your height and current weight to get the answer now.