BMI Calculator
Body mass index from height and weight.
Loading tool
Enter height and weight in metric or imperial units. The number is a population screening estimate, not a diagnosis.
How to use this tool
- Enter your measurements. Use the units shown on the labels. Do not send medical data anywhere.
- Read the estimate. These formulas are public rules of thumb, not a diagnosis.
- Talk to a clinician for decisions. Do not change medicine, diet, or training from this page alone.
Limits of BMI
BMI ignores muscle, bone, and fat distribution. Athletes and some ethnic groups are often mis-classed. A clinician can interpret it in context.
Frequently asked
Which formula is used?
Weight in kilograms divided by height in meters squared.
Are child percentiles included?
No. This page is the adult formula only.
Can I use stones?
Yes. Imperial mode accepts stones and pounds.
Does a high BMI mean I must lose weight?
This page cannot say. BMI is a screening estimate, not medical advice.
Why is my category different from a clinic chart?
Cutoffs vary slightly by organization. This page uses common WHO adult bands.