Free BMI Calculator for Adults
Calculate your BMI using metric or imperial units. See your BMI category, healthy weight range, and important limitations for adults.
Your result
Your BMI
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Add your height and weight to calculate your BMI.
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Reference range for your height
Add your height to see an adult BMI reference range.
Reference information
Add your details to see an informational estimate.
Keep viewing BMI as one screening measure, not a full picture of health.
What is BMI?
BMI, or Body Mass Index, is a simple calculation that uses your height and weight to estimate a weight category for adults.
It is often used as a screening measure, but it does not diagnose health or directly measure body fat.
BMI may be less accurate for athletes, bodybuilders, older adults, pregnant people, children, and teenagers.
Limitations of BMI
BMI is a useful screening tool, but it does not measure body fat percentage, muscle mass, bone density, or overall health. It may be less accurate for athletes, older adults, pregnant people, children, and teenagers.
Frequently asked questions
How is BMI calculated?
BMI is calculated by dividing weight in kilograms by height in meters squared.
Is BMI accurate for everyone?
No. BMI is a general screening measure and may be less accurate for some adults and is not designed for children or teenagers.
What should I do if my BMI is high or low?
Use the result as a starting point. If you have concerns, a healthcare professional can help interpret it with your health history.
Can BMI be used for children or teens?
No. This calculator is intended for adults. Children and teenagers need age- and sex-based percentile assessment.
Important to know
BMI is useful as a simple screening tool, but it is not a full picture of health.
Your BMI result is a screening estimate based on height and weight. It helps place your result in a general adult BMI category, but it does not directly measure body fat, muscle mass, or overall health. Our guide to what your BMI result means explains how to read the number with context.
This calculator is for informational purposes only and is intended for adults aged 18 and older. During pregnancy, BMI does not apply in the usual way and a different assessment is needed. The result is not a substitute for professional medical advice, diagnosis, or treatment.
How this content is maintained
T9 BMI Check is an educational resource for adults. BMI is a screening tool, not a medical diagnosis, and the information here is general rather than personalized medical advice. We research our content against trusted public-health sources, work to keep it factually accurate, and review it periodically. For guidance about your own health, please consult a qualified healthcare professional.
References
Prepared and maintained by T9 BMI Check
Last reviewed against the cited sources: July 16, 2026