BMI Calculator
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Choose your measurement preference then enter your height and weight to calculate your BMI
Your BMI is below the healthy range. You should not try to lose any weight, and putting on a few pounds may benefit your health.
Your weight is within the healthy range. Making sure you have a balanced diet and taking regular exercise will help you to stay fit and healthy. If you feel that you want to lose weight in order to feel more comfortable with your body shape, try making small, healthy changes to your eating habits and taking more exercise. You should not aim to weigh less than a BMI of 20.
The Tools in Weight Loss Resources can help you make healthy changes to your eating habits. You can see how many calories you need each day to maintain your weight or lose a few pounds.
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Your weight is above the healthy range for your height. Losing some weight would be beneficial to your health and make you look and feel better.
You don't need to do anything drastic - making sure you have a healthy, balanced diet, the right amount of calories and getting more active will help you to shift the excess pounds.
The Tools in Weight Loss Resources can help. You can set a Weight Loss goal and see how many calories you need each day to get there.
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Your weight is substantially above the healthy range for your height, which means you have a higher than average risk of developing diseases associated with obesity.
Losing enough weight to bring your BMI to below 25 will benefit your health, and the way you look and feel.
You can lose weight by making sure the number of calories you eat each day is less than the number of calories you need to maintain your weight at its current level. This is best achieved by making changes to your eating habits so your diet is healthier, and starting to get some exercise which you can build up and maintain regularly.
The Tools in Weight Loss Resources can help you make the necessary changes to your eating habits. You can set a Weight Loss goal, and see how many calories you need each day to get there.
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Your weight is substantially above the healthy range for your height, which means you have a higher than average risk of developing diseases associated with obesity.
Losing enough weight to bring your BMI to below 25 will benefit your health, and the way you look and feel.
You can lose weight by making sure the number of calories you eat each day is less than the number of calories you need to maintain your weight at its current level. This is best achieved by making changes to your eating habits so your diet is healthier, and starting to get some exercise which you can build up and maintain regularly.
The Tools in Weight Loss Resources can help you make the necessary changes to your eating habits. You can set a Weight Loss goal, and see how many calories you need each day to get there.
Take Our Free Trial »
What is BMI?
BMI stands for body mass index; a formula which relates body weight to height. It is used by health professionals and scientists to determine the health implications of being a certain weight for your height.
It's also a handy number for individuals to know, or look up from time to time, to see how healthy their current weight is. Research has shown that people who monitor their weight are less likely to put weight on and more likely to lose it.
What Your BMI Calculation Means
| Under 18.5 |
Underweight |
| 18.5 - 25 |
Healthy Weight |
| 25 - 30 |
Overweight |
| 30 - 40 |
Obese |
| Over 40 |
Severely obese |
The BMI Formula
Body mass index (BMI) = weight(kg) ÷ height(m)2
BMI is a number generated by dividing your weight in kilograms by your height in metres squared. (You can convert from stones and pounds to kilos here.)
The easiest way to work this out is to do the height multiplication first: height in meters x height in metres, then divide your weight in kilograms by the result.
Here's an example for a person who is 1.7m tall and weighs 64kg
1.7 x 1.7 = 2.89 (height x height)
64 ÷ 2.89 = 22.14 (weight ÷ height2)
So this person has a body mass index of 22.1
You can verify this result in the calculator to help the maths sink in! If you prefer seeing this type of in graphical form you can find a body mass index chart here.
Limitations of BMI as a Measure of Health
BMI is a broad measure and has 3 main limitations when it comes to determining healthy weight for an individual.
- People with a high ratio of muscle such as athletes and body builders can have a body mass index of more than 25 but still be a healthy weight. This is because BMI does not take into account the proportion of body fat a person has, and it is excess body fat that poses a risk to health, not excess muscle.
- For the same reason as in point 1, people can fall within a healthy weight range according to BMI, but still be carrying too much fat. This is especially true if fat has accumulated around the waist.
- The healthy weight range applies to both men and women. Since men generally have a larger build and have more muscle than women, they naturally weigh more. If you are setting a personal weight goal it can be helpful to look at ideal weight ranges tailored for men or women.
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