About this tool
Check adult BMI using metric or US customary measurements and review the calculation as a screening reference, not a diagnosis.
BMI Calculator is useful for quick body mass index checks when someone wants a simple height-and-weight calculation without opening a spreadsheet. It is best treated as a lightweight reference tool rather than a full health assessment.
- Synchronizes centimeters and kilograms with feet, inches, and pounds when switching measurement systems.
- Shows the converted measurements and weight-divided-by-height-squared formula behind the threshold-consistent result.
- Classifies the displayed value with CDC adult thresholds, including obesity classes 1, 2, and 3.
- Back-calculates the 18.5-inclusive to 25.0-exclusive weight reference for the entered height without presenting it as a target.
How to use BMI Calculator
Enter height and weight in the preferred units, review the BMI result, and use the category ranges only as a general adult screening reference. If the result matters for health decisions, treat this as a starting point and rely on qualified medical guidance for interpretation.
When this tool is useful
- Synchronizes centimeters and kilograms with feet, inches, and pounds when switching measurement systems.
- Shows the converted measurements and weight-divided-by-height-squared formula behind the threshold-consistent result.
- Classifies the displayed value with CDC adult thresholds, including obesity classes 1, 2, and 3.
- Back-calculates the 18.5-inclusive to 25.0-exclusive weight reference for the entered height without presenting it as a target.
Examples you can test
Load an example, compare the result with the expected output, then replace it with your own input.
Calculate BMI from metric inputs
Example input
Height: 175 cm, weight: 70 kg
Expected output
BMI estimate and category
BMI is a rough screening metric and does not measure body composition directly.
Compare a weight change
Example input
Same height, weights: 70 kg and 76 kg
Expected output
Two BMI estimates for comparison
Use comparisons cautiously because BMI categories are broad population-level indicators.
Validation checklist
- Confirm height and weight units before calculating.
- Treat BMI as a general estimate, not a medical diagnosis.
- Consult a qualified professional for health decisions.