Free, Online BMI Calculator (2024)


[[translations.imcResult]] calculImc | number_format


BMI (body mass index) is a topic that is becoming more and more relevant, giving an idea of your state of health and lifestyle. In 1997, the World Health Organisation defined BMI as the standard for assessing risks associated with obesity in adults.

Have you been wondering what your BMI is according to your weight and height?

Our BMI calculator and the following guide will give you a better idea.

The BMI indication table

The calculation of BMI is never 100% accurate unless done by a professional. Therefore, the WHO has published a table of interpretations of different BMI scores to give you a better indication of how to understand your result:

Body Mass Index (BMI)Result Meaning (according to WHO)
Less than 18.5
18.5 to 25
25 to 30
30 to 35
Moderately obese
35 to 40
Severely obese
More than 40
Morbidly obese
BMI result definitions according to WHO

This BMI interpretation table allows you to better understand the result of your BMI calculation, and therefore take action accordingly.

What is a BMI calculation?

BMI or Body Mass Index is an indicator created to estimate a person's body fat according to their weight and height. This is the only indicator validated by the World Health Organization to measures a person's body fat, determining possible health risks.

If you are looking to compare the best health insurance in Canada, then do not hesitate to use our health insurance comparator via the button below:

Compare The Best Health Insurance Plans and Rates on the market!

Get a quote

Why calculate your BMI in Canada?

There are many different reasons you may want to calculate your BMI.

For example, you might want to find out if you are at risk of having health problems. You could therefore adapt your diet and physical activity accordingly. Depending on the result of your BMI calculation, you will have to more or less reduce your diet and increase regular, physical activity.

Be careful, however, not to solely rely on the BMI result alone. Two people can have the same BMI result, yet have completely different physiques. The varies according to the distribution of bone, muscle and fat around your body, which are not taken into account when calculating BMI. Before making any big changes to your lifestyle, always consult your doctor, who will be able to give you professional advice.

What is the formula for calculating BMI?

BMI is calculated by diving a person's weight by the square of their height. A "normal" BMI calculation result is between 18.5 and 25. However, be aware this system is designed to access people between the ages of 18 and 65. If you are outside this age range, your BMI result will not be representative of the state of your health.

In order to know your BMI score quickly, use our BMI calculator at the top of this page.

Good to know

Need to convert kilograms to pounds? Our conversion tool is here to help!

How do I interpret my BMI result?

According to WHO, the different levels of BMI calculations can be categorized into different bands. Here is the interpretation of BMI results:

Under 18.5 - Your weight is too low for your height. This can be explained by pathologies but can expose a number of health hazards, such as deficiencies or anemia. We advise you to talk to your doctor who can give you more clear answers to result.

18.5 to 25 - You have a normal BMI. To maintain this, continue eating a balanced diet and engage in regular physical activity

25 to 30 - Your weight is a little too high for your height. In the long term, this may lead to health problems. Before changing your lifestyle, consult a doctor in order to gain professional advice.

Over 30 - Your weight is too high for your height. You are more exposed to metabolic diseases, heart disease or even cancer. We advise you to consult a doctor before starting any diet or lifestyle change, in order to lose weight in the safest ways possible.

To access the best health insurance quotes in Canada, use our comparator tool via the button below, and receive the best prices possible through our partners.

Compare The Best Health Insurance Plans and Rates on the market!

Get a quote

Is calculating the BMI for a women different?

The BMI calculation in general does not take into account gender. The formula always remains the same regardless. However, sometimes women tend to gain weight between the ages of 50 to 60. This is due to disturbances in the body caused by menopause, which can influence the final result of a BMI calculation.

Is calculatin the BMI for men different?

Just like there is no real difference for women, there is no real difference for men. The BMI calculator is not good enough alone to tell you if you are in a good health condition. Men with the same BMI can have a totally different physique. In fact, athletes often have a high BMI calculation result without it meaning they are obese.

Obesity in men tends to increase with age.

Good to know

If you find yourself needing to convert from metres to feet, have a look at our conversion tool!

What is a normal BMI?

A normal BMI is between 18.5 to 25. However, it is possible to get a more precise result using different formulas that take into account more specific parameters such as age, sex or morphology.

  • Bronca's formula

This formula is well known but not recommended. In fact, it has often been criticized for its simplicity and lack of precision. For example, it is known to consider an 'ideal weight' as being too heavy. The formula is as follows:

Height (cm) - 100

  • Cref's formula

This formula is a lot more effective and reliable because it uses a more advanced calculation. However, you have to work out your own morphology, which is not always easy. As a result, this calculation is more reliable for answering the question of "What is my weight for my height and age?". Here are the different calculations depending on your morphology:

  • Thinner or slender = (height - 100 + age / 10)* 0.9 squared
  • Normal = (height - 100 / 10)* 0.9
  • Larger = (height - 100 + age / 10)* 0.9 * 1.1

How to detect obesity through a BMI calculation?

According to the scale validated by the World Health Organization, a person is considered obese from the moment their BMI score is greater or equal to 30. However, it is subjective, and there are different stages of obesity.

BMI calculation scoresStage of obesity
Between 34 and 34.9
Moderately obese
Between 35 and 39.9
Severely obese
More than 40
Morbidly obese
Stages of obesity according to WHO

Obesity leads to an increased risk of developing certain health conditions, such as type 2 diabetes, high blood pressure, liver disease and many cancers.

What BMI is needed to get a gastric sleeve?

A gastric sleeve is a surgical procedure, which is restrictive and irreversible. It consists of removing approximately two-thirds of the stomach, intended for people who are severely overweight or morbidly obese. In Canada, people with a BMI over 35 with health conditions are eligible for the procedure.

How to calculate the BMI of a teenager?

Officially, there is no way to calculate the BMI of a teenager. In fact, the BMI scale was created for people between the ages of 18 to 65. Therefore, using a BMI calculator for a teenager would give an inaccurate result, being totally inappropriate.

However, there are now indicative body build curves available to give you an idea of the 'norm', depending on your teenager's height - which is, therefore, a good substitution for BMI calculations.

Does BMI calculation vary with age?

The calculation of BMI does not vary exactly according to age, but it only applies to the age group 18 to 65. Within this age group, BMI calculation doesn't change, regardless of gender. However, it does not apply to anyone outside this age group, or those who are pregnant.

Is calculating BMI relevent for pregrant women?

No, it is not relevant. Do not try to use a BMI calculator if you are pregnant, because the result will not be valid at all. If you make any lifestyle changes due to a BMI result, then this could expose you to many serious health problems.

What is the ideal BMI to become a model?

In order to prevent models from putting themselves in danger, a minimum BMI threshold was imposed on them to be able to exercise. Therefore, it is forbidden in several countries, to use models whose BMI is lower than 18.5.

Did you like this article?
Alexandre Desoutter

Alexandre Desoutter has been working as editor-in-chief and head of press relations at HelloSafe since June 2020. A graduate of Sciences Po Grenoble, he worked as a journalist for several years in French media, and continues to collaborate as a as a contributor to several publications.