The benefits of maintaining a healthy weight go far beyond improved energy and smaller clothing sizes. By losing weight or maintaining a healthy weight, you are also likely to enjoy these quality-of-life factors too.
- Fewer joint and muscle pains
- More energy and greater ability to join in desired activities
- Better regulation of bodily fluids and blood pressure
- Reduced burden on your heart and circulatory system
- Better sleep patterns
- Reductions in blood triglycerides, blood glucose, and risk of developing type 2 diabetes
- Reduced risk for heart disease and certain cancers
BMI is an indicator of the amount of body fat for most people. It is used as a screening tool to identify whether an adult is at a healthy weight. Find your BMI and what it means with our handy BMI Calculator. A separate BMI Percentile Calculator should be used for children and teens that takes a child’s age and gender into consideration.
- BMI stands for Body Mass Index
This is a numerical value of your weight in relation to your height. A BMI between 18.5 and 25 kg/m² indicates a normal weight. A BMI of less than 18.5 kg/m² is considered underweight. A BMI between 25 kg/m² and 29.9 kg/m² is considered overweight. A BMI of 30 kg/m² or higher is considered obese.
- Excess weight increases the heart's work.
It also raises blood pressure and blood cholesterol and triglyceride levels and lowers HDL (good) cholesterol levels. It can make diabetes more likely to develop, too. Lifestyle changes that help you maintain a 3-5% weight loss are likely to result in clinically meaningful improvements in blood glucose, triglycerides, and risk of developing type 2 diabetes. Greater weight loss can even help reduce BP and improve blood cholesterol.
- To calculate your BMI:
- Type your height and weight into the online BMI calculator from NIH.
Your body is made up of water, fat, protein, carbohydrate and various vitamins and minerals. If you have too much fat — especially if a lot of it is at your waist — you're at higher risk for such health problems as high blood pressure, high blood cholesterol and diabetes. That increases your risk for heart diseases and stroke.
Obesity is now recognized as a major, independent risk factor for heart disease. If you're overweight or obese, you can reduce your risk for heart disease by successfully losing weight and keeping it off.
Waist circumference and body mass index (BMI) are indirect ways to assess your body composition. Waist-to-hip ratio (WHR) is another index of body fat distribution. However, WHR is less accurate than BMI or waist circumference and is no longer recommended.
Check your Body Mass Index using the NHLBI BMI Calculator for adults.
Questions About BMI
What is the waist circumference?Waist circumference is the distance around your natural waist (at the iliac crest – or hip bone). If your BMI is between 25-35 kg/m2, your goal for waist circumference is less than 40 inches if you're a man and less than 35 inches if you're a woman.
What is the body mass index (BMI)?BMI is an indicator of the amount of body fat for most people. It is used as a screening tool to identify whether an adult is at a healthy weight in kilograms is divided by height in meters squared (kg/m2). In studies by the National Center for Health Statistics,
- BMI values less than 18.5 kg/m² are considered underweight.
- BMI values from 18.5 kg/m² to 24.9 kg/m² are healthy.
- Overweight is defined as a body mass index of 25.0 to less than 30.0 kg/m². People with BMIs in this range have an increased risk of type 2 diabetes, hypertension, and cardiovascular disease.
- Obesity is defined as a BMI of 30.0 kg/m² or greater. People with BMIs of 30 kg/m² or more are at higher risk of cardiovascular diseases.
- Extreme obesity is defined as a BMI of 40 kg/m² or greater.
Some well-trained people with dense muscle mass may have a high BMI score but very little body fat. For them, the waist circumference, the skinfold thickness or more direct methods of measuring body fat may be more useful measures than BMI.
How do you find your BMI risk level?
- Use a weight scale on a hard, flat, uncarpeted surface. Wear very little clothing and no shoes.
- Weigh yourself to the nearest pound.
- With your eyes facing forward and your heels together, stand very straight against a wall. Your buttocks, shoulders and the back of your head should be touching the wall.
- Mark your height at the highest point of your head. Then measure your height in feet and inches to the nearest 1/4 inch. Also figure your height in inches only.
- Find your height in feet and inches in the first column of the Body Mass Index Risk Levels table. The ranges of weight that correspond to minimal risk, moderate risk (overweight) and high risk (obese) are shown in the three columns for each height.
(BMI under 25)
(BMI 30 and above)
|4'10"||118 lbs. or less||119–142 lbs.||143 lbs. or more|
|4'11"||123 or less||124–147||148 or more|
|5'0||127 or less||128–152||153 or more|
|5'1"||131 or less||132–157||158 or more|
|5'2'||135 or less||136–163||164 or more|
|5'3"||140 or less||141–168||169 or more|
|5'4"||144 or less||145–173||174 or more|
|5'5"||149 or less||150–179||180 or more|
|5'6"||154 or less||155–185||186 or more|
|5'7"||158 or less||159–190||191 or more|
|5'8"||163 or less||164–196||197 or more|
|5'9"||168 or less||169–202||203 or more|
|5'10"||173 or less||174–208||209 or more|
|5'11"||178 or less||179–214||215 or more|
|6'0"||183 or less||184–220||221 or more|
|6'1"||188 or less||189–226||227 or more|
|6'2"||193 or less||194–232||233 or more|
|6'3"||199 or less||200–239||240 or more|
|6'4"||204 or less||205–245||246 or more|
To calculate your exact BMI value, multiply your weight in pounds by 703, divide by your height in inches, then divide again by your height in inches. (Adapted from Obesity Education Initiative: Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, National Institutes of Health, National Heart, Lung, and Blood Institute, Obesity Research 1998, 6 Suppl 2:51S-209S)
Last reviewed on 08/2014.