Before calculating
Prepare Units, Height, Additional height and Weight. Match each input to the document, measurement, or current source you are using. Keep units, dates, currency, and time periods consistent.
HEALTH REFERENCES WITH CLEAR LIMITS
Adult BMI Calculator
Calculate body mass index for adults age 20 and older using U.S. customary or metric measurements.
Review your result
Your result
Ready when you are.
Enter your values and select Calculate. Your result stays on this device.
How it works
U.S. customary BMI = weight in pounds ÷ height in inches² × 703. Metric BMI = kg ÷ m².
Assumptions
For adults age 20+. BMI is a screening measure and does not diagnose disease or assess every aspect of health.
Use case
BMI calculator: a clear planning check
Calculate body mass index for adults age 20 and older using U.S. customary or metric measurements. The stated formula, assumptions, and result limits remain visible so the calculation can be checked in context.
Use a clear BMI calculator scenario with values you can verify before relying on the result.
Build a reliable scenario
How to use and verify your Adult BMI Calculator result
Adult BMI Calculator helps you check a specific health & family question with figures that apply to you. Calculate body mass index for adults age 20 and older using U.S. customary or metric measurements. Calculate body mass index for adults age 20 and older using U.S. customary or metric measurements. The stated formula, assumptions, and result limits remain visible so the calculation can be checked in context. Use a clear BMI calculator scenario with values you can verify before relying on the result. The page keeps the method and limits visible so the result can be understood, compared, and checked instead of treated as an unexplained answer.
What changes the result?
The stated method is: U.S. customary BMI = weight in pounds ÷ height in inches² × 703. Metric BMI = kg ÷ m². Change one assumption at a time to see which input drives the result, then compare scenarios on the same basis.
When checking the answer
For adults age 20+. BMI is a screening measure and does not diagnose disease or assess every aspect of health. Not medical advice. BMI categories differ for children and teens; discuss personal health concerns with a qualified clinician.
Quick verification checklist
- • Confirm the date and unit of every input.
- • Replace defaults with values that match your case.
- • Compare the answer with a second scenario.
- • Use the official source for regulated or high-impact decisions.
Source and update
Last reviewed: 2026-08-08
CDC Adult BMI Calculator and guidanceFrequently asked questions
Is Adult BMI Calculator free to use?
Yes. This calculator runs in your browser and does not require an account.
Is the result guaranteed?
For adults age 20+. BMI is a screening measure and does not diagnose disease or assess every aspect of health.
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