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Body Mass Index Calculator

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Result: kg/m2
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Metric Units

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Result: kg/m2
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About our BMI Calculator


A2Z Tools bring you the BMI calculator that is free and easy to use. This free BMI (Body Mass Index) calculator gives the accurate BMI value and characterizes BMI based on the provided information. Use our free BMI calculator to monitor your body mass index (BMI) and check if you are a healthy weight. Furthermore, you can use our BMI calculator to check your children's BMI.


Learn what is BMI


The ideal BMI varies from person to person based not only on height and weight but also on other factors. The body mass index or BMI helps people find if their weight is right for their height. One way to determine how healthy you are is by calculating your BMI. For BMI calculation, you need to know your weight in kilograms and height in meters, and to divide your weight in kilograms by your height in meters squared. 


If you know your weight in pounds and height in inches, you can calculate your BMI still. Body mass index (BMI) is not the only factor that studies your overall health. Once you get the results, this calculator will allow you to measure the ratio of waist circumference to height. Use our body mass index (BMI) calculator to determine if your height is overweight or overweight. For most adults, BMI is a good estimate of the health risks associated with weight. BMI is calculated the same way in children as in adults, but healthy and unhealthy ranges are defined differently. Compare the child’s BMI value with other children of the same age and sex, and calculate a percentile: if the child’s BMI is lower than the 5th percentile, they are considered underweight, if their BMI is higher than the 95th percentile Percentile, they are considered obese. A score below 20 means you may be overweight, and a reading above 25 means you may be overweight. 


Ideal BMI


When remembering that people with a BMI between 18.5 and 24.9 have ideal body weights, studies show that if a person has a BMI of 40+, this indicates an extremely high risk for obesity-related diseases and even premature death. Ideally, to achieve a healthy weight range you should consult your doctor and consider losing 5-10% of your weight. The BMI Calculator will provide you with a personalized calorie counting system to help you reach a healthy weight safely. If obese or underweight, having serious health consequences can cause serious health problems; so while BMI is an imperfect indicator of healthy body weight, it is a useful indicator of the need for further research or action. 


However, BMI is a fairly indicative measure of body fat for 90-95% of the population and can be used effectively to determine healthy body weight. The Weight Index (PI) is similar to BMI in that it measures how thin or fat a person is based on their height and weight. While PI suffers from similar considerations, PI is more reliable for use with very tall or short people, while BMI tends to record unusually high or low body fat levels for very high or very overweight people. Aside from these limitations, BMI is a relatively simple and affordable way to measure weight. The National Institutes of Health (NIH) has now identified BMI as a crucial parameter for determining whether you are overweight or obese, underweight, normal weight, overweight or underweight. Along with your BMI, identifying your waist circumference can help you determine if you are overweight and at risk for heart disease and type 2 diabetes. 


BMI for children and adolescents between the age of 2 and 18 years old, the BMI calculator takes into consideration age and gender, as well as height and weight. Since muscle mass tends to decline in older people and body fat tends to increase, the BMI may not reflect body fat accurately if you are over 60. A recent study comparing BMI, waist circumference, waist-to-hip ratio, and waist-to-height ratio found that waist-height ratio is the most accurate way to predict body fat because BMI is based on the relationship between height and weight. Different, so your gender is not important.