BMI Calculator
Compute body mass index from weight (kg) and height (m).
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Weight
- 70 kg
- Height
- 1.75 m
Result: BMI 22.9 (Normal)
The tool opens with these values already filled in. Replace them with your own.
What you enter
- Weight
- Height
What this is
Sophie Well returns the numeric BMI and the WHO category (Underweight, Normal, Overweight, Class I-III obesity). BMI is a population-level screening number, not a body-composition measurement; muscle mass, frame size, and ethnicity all shift its clinical interpretation.
When to use it
Use this whenever a clinical formula or guideline asks for BMI - bariatric eligibility, anesthesia risk stratification, pediatric percentile lookup (use the age-and-sex-specific CDC curves for that, not this), or simple charting. Body Surface Area (Du Bois or Mosteller) is a separate tool and is usually what chemotherapy and pediatric dosing want.
How this is calculated
Quetelet 1835; Keys A, et al. Indices of relative weight and obesity. J Chronic Dis. 1972;25(6). Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.