Adult BMI calculator
Calculate an adult body mass index from height and weight.
Enter your values, then calculate.
Your calculation stays in your browser.
The formula, explained
BMI = weight (kg) ÷ height (m)²For adults aged 18 and over, excluding pregnancy. BMI is a screening measure, not a diagnosis: it does not directly measure body fat and its thresholds do not fit every situation. Children need age- and sex-specific growth charts and professional interpretation.
Source and reference : NHS ↗
An example to check
Using the starting values below, the calculation gives:
Within the reference range — Your BMI falls in the adult “within the reference range” category: from 18.5 to below 25 kg/m².
How to use this tool
Check the required inputs: weight, height, age.
Choose the units and options that match your task. Calculate, check the result and use Copy or Print to keep a record. Rounding applies to the display; keep more precision in intermediate steps.
Can I use a decimal comma?
Yes. Numeric fields accept 12.5 or 12,5 and spaces for thousands, such as 1 234.50. Do not mix a point and comma in one number.
Where are my inputs processed?
Calculations run in your browser. Form values are not sent to Analytics. Copying, printing, sharing or opening an external service is your choice.
Method and interface checked on 2026-09-19 · Report an error