BMI Calculator — Calculate Body Mass Index Free Online
UtilityCalculate your BMI in kg or lbs. Get your health category, ideal weight range, and how much to lose or gain. Supports metric and imperial. Free BMI calculator online.
About the BMI Calculator — Calculate Body Mass Index Free Online
Our free BMI calculator helps you calculate your Body Mass Index — a widely used measure that estimates whether your weight is in a healthy range for your height. BMI is calculated by dividing your weight in kilograms by the square of your height in metres. While BMI is a useful screening tool, it is important to understand that it is not a direct measure of body fat and does not account for muscle mass, age, or body composition. Always consult a healthcare professional for personalised medical advice.
How to Use the BMI Calculator — Calculate Body Mass Index Free Online
- 1
Select your preferred unit system — metric (kg/cm) or imperial (lbs/inches).
- 2
Enter your height in the height field.
- 3
Enter your weight in the weight field.
- 4
Click Calculate BMI to see your result instantly.
- 5
View your BMI score and which category it falls into — Underweight, Normal, Overweight or Obese.
Frequently Asked Questions
What is a healthy BMI range?
According to the World Health Organisation (WHO), a BMI between 18.5 and 24.9 is considered a healthy weight. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is classified as obese. These ranges apply to adults aged 18 and over.
Is BMI an accurate measure of health?
BMI is a useful population-level screening tool but has limitations for individuals. It does not measure body fat directly and cannot distinguish between muscle and fat mass. Athletes with high muscle mass may have a high BMI despite being very healthy.
How is BMI calculated?
BMI is calculated by dividing your weight in kilograms by the square of your height in metres. For example, a person who weighs 70kg and is 1.75m tall has a BMI of 70 ÷ (1.75 × 1.75) = 22.9, which is in the healthy range.
Does BMI differ for children?
Yes. BMI for children and teens aged 2 to 19 is calculated differently — it is compared against age and sex specific growth charts rather than fixed cut-off points. This calculator is designed for adults. For children, consult a healthcare provider.
What should I do if my BMI is outside the healthy range?
If your BMI is outside the healthy range, the most important step is to speak with your doctor or a registered dietitian. They can assess your individual situation and recommend appropriate steps if needed.
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