Adult BMI Calculator – Online Tool

Your measurements

Choose your units, then enter the details you want to use.

Your estimate will appear here

Complete the relevant fields and select Calculate. Changes to your inputs clear the previous result.

Educational estimates, with their equations and assumptions. They do not diagnose a condition or prescribe a treatment.

Method, assumptions & sources

Who this is for

Adults aged 20 or older, outside pregnancy.

How it works

BMI = weight in kg ÷ height in metres squared. Reference thresholds use the unrounded result: 18.5, 25, 30, 35 and 40. Rounded display numbers do not change the classification.

Keep in mind

BMI is a screening measure; it cannot separate muscle, bone and fat or diagnose health.
Adult reference bands do not apply to children or pregnancy.

Sources

CDC: adult BMI calculator and reference categories (opens in a new tab)