Calculate your Body Mass Index - Standard BMI

How to calculate your BMI (Body mass index)

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

So the body mass index formula is as follows:

BMI = weight / height².

Basic 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

Using the body mass index calculator

Please enter your height and weight in our BMI calculator and "check" these, you'll have your BMI and a little message telling you generally about your health status.

Why Is a Healthy Weight Important?

Reaching and maintaining a healthy weight is important for overall health and can help you prevent and control many diseases and conditions. If you are overweight or obese, you are at higher risk of developing serious health problems, including heart disease, high blood pressure, type 2 diabetes, gallstones, breathing problems, and certain cancers. That is why maintaining a healthy weight is so important: It helps you lower your risk for developing these problems, helps you feel good about yourself, and gives you more energy to enjoy life. 

What Is Overweight and Obesity?

Overweight is having extra body weight from muscle, bone, fat, and/or water. Obesity is having a high amount of extra body fat. Body mass index (BMI) is a useful measure of overweight and obesity. The information on this Web site will provide you with information about BMI (including limitations of this measure) and how to reach and stay at a healthy weight. Talk to your health care provider if you are concerned about your BMI.

What Factors Contribute To a Healthy Weight?

Many factors can contribute to a person’s weight. These factors include environment, family history and genetics, metabolism (the way your body changes food and oxygen into energy), and behavior or habits.

What are the health consequences of obesity for adults?

People who have obesity are at increased risk for many diseases and health conditions, including the following:

  • All-causes of death (mortality)
  • High blood pressure (Hypertension)
  • High LDL cholesterol, low HDL cholesterol, or high levels of triglycerides (Dyslipidemia)
  • Type 2 diabetes
  • Coronary heart disease
  • Stroke
  • Gallbladder disease
  • Osteoarthritis (a breakdown of cartilage and bone within a joint)
  • Sleep apnea and breathing problems
  • Chronic inflammation and increased oxidative stress
  • Some cancers (endometrial, breast, colon, kidney, gallbladder, and liver)
  • Low quality of life
  • Mental illness such as clinical depression, anxiety, and other mental disorders
  • Body pain and difficulty with physical functioning

Energy Balance

Energy balance is important for maintaining a healthy weight. The amount of energy or calories you get from food and drinks (energy IN) is balanced with the energy your body uses for things like breathing, digesting, and being physically active (energy OUT):

  • The same amount of energy IN and energy OUT over time = weight stays the same (energy balance)
  • More energy IN than OUT over time = weight gain
  • More energy OUT than IN over time = weight loss

To maintain a healthy weight, your energy IN and OUT don’t have to balance exactly every day. It’s the balance over time that helps you maintain a healthy weight.

You can reach and maintain a healthy weight if you:

  • Follow a healthy diet, and if you are overweight or obese, reduce your daily intake by 500 calories for weight loss
  • Are physically active
  • Limit the time you spend being physically inactive
Find out more calculators on Health and Fitness