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BMI calculator
Calculate adult body mass index using metric or US customary units.
For adults aged 20+. General reference, not a medical diagnosis.
RESULT
22.49 BMI
Healthy weight
The category uses the unrounded value.
How it works
BMI = weight in kilograms ÷ height in meters squared. CDC adult categories are underweight below 18.5, healthy weight from 18.5 to below 25, overweight from 25 to below 30, and obesity at 30 or above. Categories use the unrounded result.
How to use
- Choose metric or feet/inches and pounds.
- Enter your height and weight.
- Read the BMI and adult reference category.
Worked examples and common mistakes
At 170 cm and 65 kg, convert height to 1.70 m: BMI = 65 ÷ (1.70 × 1.70) ≈ 22.5. Squaring 170 without converting centimetres gives the wrong units. With imperial input, enter feet and inches in their separate fields.
The displayed categories follow the CDC reference for adults aged 20 and older. BMI alone cannot determine body fat or an individual’s health. Do not apply these adult categories to children or teenagers. Use the result as a reference, and discuss personal health questions with a qualified professional.
Frequently asked questions
Does BMI diagnose my health?
No. BMI is a screening measure, not a diagnosis or a direct measurement of body fat. A clinician can interpret it alongside other information.
Can children use these categories?
The fixed categories shown are for adults aged 20 or older. Children and teens require an age- and sex-specific assessment.