BMI Calculator

Calculate BMI easily with our free online BMI calculator. The BMI index calculator shows you how to calculate BMI in a snap!

Body Mass Index (BMI) is a measurement of body fat based on weight. We have a BMI calculator for females and a BMI calculator for males. This BMI calculator that we provide is free and gives a basic idea of your body mass index.

The definition of body mass index or BMI is the amount of fat content in the body as related to your height and weight. This is a way of measuring the fat content and muscle mass so that the person knows whether they are healthy or whether they can be prone to health problems like cardiovascular diseases, diabetes, or even certain types of cancer.

Watching your BMI helps you to maintain the right weight and also the right proportion of bone density and muscle and to reduce the fat content in case it is high. There are certain risks involved if your body mass index is on the high side or even if it is too low.

Our free online BMI calculator helps you to calculate your own personal body mass index so you can change your lifestyle and eating habits and bring it around to the right amount. Most people need to include exercise in their daily routine and also to cut out fats and sugars to maintain the right body mass index.

For those who have a high BMI there are possibilities of their suffering from urinary stress, gastro esophageal reflux, infertility in females, osteoarthritis, sleep apnea, type II diabetes, cardiovascular disease, and hypertension. BMI is a good indicator of what your health hazards could be. Take action and maintain the right BMI today!

In a time when our culture seems to be obsessed with weight, fitness, eating right, and exercising, the term BMI or Body Mass Index is mentioned often in fitness circles and physician’s offices. Over the last 40 years, many doctors have shifted their focus from weight to BMI when it comes to determining the health of their patients. However, many people do not understand what BMI is or how it is used to determine a person’s overall health. Understanding this term and how it relates to weight loss and health can help an individual achieve the healthiest weight for their body.

What is BMI?

Your Body Mass Index is figured in a percentage once a calculation is made based on your height and weight. To figure BMI a person’s weight is divided by the square of their height. Don't worry, there are many free websites online that will perform the calculation for you in seconds. It's important to note that calculations for children and adults are different and different calculators are used for this purpose.

This percentage is then applied to a chart that determines if the person is underweight, normal weight, overweight, or obese. BMI is a better determiner of healthy body weight than weight alone because it height takes into consideration. For example, if you weigh 180 pounds, a doctor can't label you as overweight or underweight without considering how tall you are. A person weighing 180 pounds and being 6’2” is a normal weight; however, a person weighing 180 pounds and standing 5’2” is considered obese. BMI takes into consideration both factors to determine a healthy weight for people of differing heights.

How was the concept of BMI developed?

BMI was invented by Adolphe Quetelet in the early 1800s while he was conducting a social experiment in body image. It was referred to as the Quetelet Scale. The phrase “body mass index” was developed by Ancel Keys in the early 1970s, just like Quetelet, as part of a social study on weight and obesity. The term BMI stuck and became popular among fitness professionals, individuals and doctors.

Keys did not like BMI being used in this way as he developed the phrase to be applied to studying population groups as a whole not individuals. He meant for the overall BMI of a culture or geographically located people group to be calculated to help determine diseases, physical inactivity, and risk factors. None the less, BMI has now become a staple in the doctor’s office and in the gym.


What do BMI numbers mean and how are they used?

Now that BMI is commonly used, it should be understood what the numbers mean. Generally a BMI of 18.5 to 25% indicates a normal, healthy weight. A BMI under 18.5% means a person is underweight, and a BMI from 26-30% means a person is overweight. A BMI over 30% means a person is obese, and a BMI under 18.5% means a person is too thin with a number below 17.5% indicating a person many be suffering from anorexia nervosa.

The numbers are used in many ways. First of all, BMI is used by doctors to asses to overall health of their patients. Determining if a person is overweight or underweight can help a doctor better treat health conditions, even preventing or reversing some conditions that have to do with weight. Some doctors prefer not to use BMI as a determining factor in assessing health. They prefer to assess the overall life style of patients, habits, and family history.

This index is used by personal trainers and fitness professionals to determine the weight lose or weight gain goals of their clients. It is a starting point in setting an overall fitness plan. Incremental goals such as adding to or subtracting from a person’s BMI number are easier to measure and obtain and indicate more results than just a number on a scale.

Some insurance companies use these percentages when determining a person’s premium rates and coverage. The National Institutes of Health and the World Health Organization have both adopted BMI numbers as a determining factor in the overall health and health risks of individuals. Many insurance companies have adopted this as well. Insurance companies may ask for a person’s BMI when they are applying for health insurance and/or life insurance. If BMI is too high, an individual may be denied insurance or charged a higher premium rate.

BMI is used by local, state, and federal government agencies to determine the risk factors of the people they govern. A recent survey showed that 59% of men and 49% of women in America have a BMI over 25 making them overweight. The survey also indicated that 4% of American women and 2% of American men are morbidly obese. The government than takes these numbers into consideration when allocating funding for programs, hospitals, and education needs in the community.

What are some limitations of BMI?

BMI has its limitations and some doctors and educators are lobbying for significant changes. The main limitation of BMI is that it only takes into consideration weight and height. Though it is a step above simply using a person’s weight to determine health, there are many factors left out of the BMI calculations.

For example, a person’s bone density and size are not taken into consideration. Some people are referred to as big-boned. This is not just an alternate term to fat, as some people believe. There are actually different bone sizes and densities within people. This is determined by ethnicity, family history, and other factors. Bone density is not taken into consideration when determining a person’s Body Mass Index.

Muscle mass is also not taken into consideration. A body builder may have little to no fat on their body, but their BMI number may indicate that they are overweight because of the size and mass of their muscles. Just as with bones, muscle mass is different in different people. On the other hand, a person may be determined healthy by BMI but have no muscle mass to their body. Muscle to fat ratio is an important factor that is left out of these calculations.

Harmful habits such as smoking, drinking, and drug use are other important factors outside the realm of body mass. A person may be classified as healthy due to BMI, but actually be very unhealthy and at high risk do to lifestyle choices. The same goes for family history. A person with a normal body weight as determined by BMI may be a risk for heart disease or cancer due to family history, exposure, or other factors.

Conclusions of Using Body Mass Index

Though the application of BMI for individuals was not the purpose of those who invented and expanded on the calculations, it has become a popular and effective determining factor used by many people. However, it should not be the only determining factor and it should not be used as the only indicator in an overall fitness program.

Knowing your Body Mass Index is an appropriate starting point for weight loss, as a way to maintain a healthy weight, as well as a way to increase weight in those who are underweight. When the limitations are taken into consideration and other factors of health are assessed, BMI can be a fair assessment of a person’s weight and health.

Use the free online BMI calculator now!