How this BMI calculator works
The calculator converts height to meters and weight to kilograms, then divides weight by height squared. US inputs are converted before the formula is applied.
Adult BMI categories and source context
When category context is shown, the labels follow CDC adult BMI category thresholds. They are shown as screening context only and are not a diagnosis or a full health assessment.
What BMI does not include
BMI does not directly measure body fat, muscle, bone mass, fat distribution or overall health. This adult tool is not designed for children or teens, pregnancy, eating disorder contexts or medical diagnosis.
Key terms and assumptionsFormula notes, key terms, source assumptions and limits used in this calculator.
- Adult-only scope
- This calculator is scoped to adults and is not designed for children or teens, pregnancy, eating disorder contexts or diagnosis.
- BMI formula
- BMI equals weight in kilograms divided by height in meters squared. US inputs are converted before calculation.
- Category context
- CDC adult BMI category thresholds are shown as screening context only, not as a health-status diagnosis.
- Formula limits
- BMI does not directly measure body fat, muscle, bone mass, fat distribution or overall health.
Related calculators
Browse the Health & Fitness calculators hub for related calculators.
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FAQs
What does BMI mean?
BMI is body mass index, a number calculated from weight and height.
Is BMI a diagnosis?
No. BMI is a screening-style measure and should not be used as a diagnosis.
Does BMI measure body fat?
No. BMI does not directly measure body fat, muscle, bone mass or fat distribution.
Is this calculator for children or teenagers?
No. This calculator is for adults only. Children and teenagers use age- and sex-specific growth-chart methods.
Can BMI be misleading for athletes?
Yes. Higher muscle mass can affect BMI because BMI only uses height and weight.
Can I use BMI during pregnancy?
This calculator is not designed for pregnancy.
Why does the category use source-based wording?
Adult BMI category names and thresholds should match the cited source and be shown as context, not diagnosis.
Can I copy my result?
Yes. The copy summary includes the entered values, BMI estimate and limitation note.