Adult BMI calculator
Calculate body mass index from height and weight in metric or imperial units, with adult CDC category ranges. Change the inputs to update the chart or diagram.
Your inputs
The editable example is illustrative. Enter your own dimensions, operating data, prices, and fees. Results update as you edit.
Calculations run in your browser. Inputs are not saved or sent to analytics.
How it works
- Body mass index (BMI) = kg ÷ m²
- 1 lb = 0.45359237 kg; 1 in = 0.0254
- Worked example: 70 kg ÷ (1.75 m)² ≈ 22.857
Input and formula key
Your result
Complete the inputs to see your result.
Assumptions and limitations
Uses CDC categories for adults aged 20 and over: underweight below 18.5; healthy weight from 18.5 to below 25; overweight from 25 to below 30; obesity from 30. Classification uses the unrounded result. BMI does not distinguish fat from muscle or bone. A clinician can interpret it alongside other health information.
Sources
- CDC — adult BMI categories, ages 20 and over Sources reviewed: 2026-10-22
- CDC — BMI limitations and interpretation Sources reviewed: 2026-10-22
