Quick guide
How to use this calculator
- Use the labels and unit notes to enter the requested measurement, date, time, or observation exactly as recorded.
- Check the visible method, population, and unit basis before using the result; switch modes rather than converting values mentally.
- Read the calculation audit and limitations together. The result supports measurement or tracking and does not replace diagnosis, treatment, or urgent medical assessment.
Calculation method
How the adult bmi calculator works
BMI = weight in kilograms ÷ height in metres². Imperial entries are converted to kilograms and metres before evaluation.
BMI is a population screening measure and an indirect proxy for adiposity. Waist measures, health history, body composition, age, pregnancy, ethnicity, and muscularity can materially affect interpretation.
Worked example
Adult BMI example
An adult weighing 70 kg at 1.75 m has a BMI of 22.86 kg/m², which falls in the WHO 18.5–24.9 screening band.
BMI = weight in kilograms ÷ height in metres². Imperial entries are converted to kilograms and metres before evaluation.
Supported inputs
Precision and limits
Supported purpose
Supported only for adults aged 20–120. It does not apply pediatric growth references, diagnose a condition, or determine an individual treatment or target weight.
Measurement quality
The output is only as reliable as the entered measurement, device, timing, units, and applicable reference population. Recheck unexpected values against the original record.
Clinical boundary
This calculator does not diagnose a condition, choose treatment, change medication, or determine that an urgent symptom is safe to monitor at home. Contact an appropriate health professional or local emergency service when the situation may be urgent.
Privacy
Entered health values and results stay in this browser tab. They are not placed in URLs, analytics, logs, local storage, session replay, or a cloud record by this calculator.
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