Calculator guide
BMI helps you explore the stated health question. Start with the labelled inputs, then review the method, worked example and limitations before using a result.
Formula or method
BMI = weight in kilograms ÷ height in meters². In US customary units, BMI ≈ 703×weight in pounds÷height in inches².
How to use this calculator
- Enter height and weight in the selected units.
- Read the adult screening category; this does not diagnose health or establish a personal target weight.
Worked example
A weight of 70 kg and height of 1.75 m gives BMI = 70÷1.75² ≈ 22.9.
Understanding the result
Compare the output with the bmi worked example using exactly the same inputs. A different assumption or rounding convention can produce a different displayed result; the output does not establish personal or professional suitability.
Limitations and assumptions
- Adult categories are screening conventions, not a diagnosis. Children require age- and sex-specific percentiles, and pregnancy or muscular build changes interpretation.
- The worked example demonstrates the stated assumptions, not a recommendation about your personal circumstances.
Frequently asked questions
Which inputs should I check first?
Follow the BMI input instructions above. Check each measurement, date, selection or expression before comparing results.
Why might my result differ from another tool?
Compare the other tool's bmi method, input units, rounding and assumptions. A matching title does not guarantee that both tools answer the same question.
Does a linked reference certify this result?
No. A reference can explain a formula or provide background for BMI, but it does not endorse this website, validate personal inputs or establish professional suitability.
Sources
Educational and planning information only. Sources are attributed background or formula references, not endorsements. Verify consequential decisions with an appropriate qualified professional.