BMI Calculator
Calculate body mass index from height and weight. Use metric or imperial units.
BMI calculator inputs
Input
Unit system
Result
Enter height and weight
BMI is a simple screening measure and does not account for age, body composition, or medical history.
About BMI
About BMI
BMI is calculated from height and weight using . It can be useful as a quick estimate, but it is not a diagnosis or a complete measure of health. There are more accurate ways to assess body composition. For a detailed breakdown, see the BMI reference [1].
FAQ
FAQ
What is BMI?
BMI, or body mass index, is a simple ratio of body weight to height. It is commonly used as a quick screening measure for weight categories, not as a full health assessment.
How is BMI calculated?
For metric inputs, BMI is weight in kilograms divided by height in meters squared. For imperial inputs, this calculator uses pounds divided by inches squared, multiplied by 703.
What do the BMI categories mean?
This calculator uses common adult BMI cutoffs: underweight is below 18.5, healthy weight is 18.5 to below 25, overweight is 25 to below 30, and obesity is 30 or higher.
Is BMI accurate for everyone?
No. BMI does not directly measure body fat and does not account for muscle mass, bone density, pregnancy, age, sex, ethnicity, or medical history. Athletes and people with unusual body composition can have misleading BMI results.
Should children or teenagers use this BMI calculator?
This calculator uses adult BMI categories. Children and teenagers are usually assessed with age- and sex-specific BMI percentiles, so their results should be interpreted with pediatric growth references instead.
Is this medical advice?
No. The result is an educational screening estimate. If you have concerns about weight, nutrition, body composition, or health risk, discuss them with a qualified health professional.
Related tools
Height Percentile Calculator
Compare your height to country specific reference data.
References
References
[1] Body mass index
Wikipedia
Wikipedia contributors. Body mass index. Wikipedia, The Free Encyclopedia.
How this tool uses the data
The BMI formula and adult category cutoffs used by this calculator come from the referenced Wikipedia BMI page. The tool applies those thresholds to the height and weight you enter; it does not fetch live data or provide medical advice.