What is a healthy BMI range?

The WHO defines 18.5–24.9 as the healthy range for adults. Below 18.5 is underweight, 25.0–29.9 is overweight, and 30+ is obese.

Is BMI accurate for athletes?

BMI does not distinguish muscle from fat. Highly muscular individuals may register as overweight despite low body fat. For better accuracy, combine BMI with body composition measurement.

Does BMI work for children?

Children use age- and sex-specific BMI percentiles, not the adult categories. This tool is for adults aged 18+.

What are the BMI categories?

Underweight: below 18.5. Normal weight: 18.5–24.9. Overweight: 25.0–29.9. Class I obesity: 30.0–34.9. Class II obesity: 35.0–39.9. Class III obesity: 40 or above.

Is BMI different for older adults?

For adults over 65, some guidelines suggest a slightly higher BMI (around 22–27) may be protective. Always consult a healthcare provider for personalized guidance.

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BMI Calculator

Calculate your Body Mass Index in metric or imperial units — instant result, no signup.

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About this tool

Body Mass Index estimates body fat from weight and height. Use this tool with metric (kg/cm) or imperial (lb/in) units to see your BMI and the WHO category it falls in.

How to use

1 Select your preferred unit system: metric (kg/cm) or imperial (lb/in).
2 Enter your weight and height.
3 Your BMI is calculated instantly along with the WHO category.
4 Review the healthy weight range for your height shown below the result.

Frequently Asked Questions

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