About the BMI Calculator
Body Mass Index (BMI) is a simple screening number that relates your weight to your height. It's widely used as a quick, rough guide to whether someone is in a healthy weight range for their height, and it places the result into categories from underweight to obese.
Enter your height and weight in metric or imperial units and this calculator shows your BMI and its category instantly, in your browser. BMI is a general indicator, not a diagnosis — see the note below.
How to use it
- 1Choose metric (cm, kg) or imperial (ft/in, lb) units.
- 2Enter your height.
- 3Enter your weight.
- 4Read your BMI value and which category it falls into.
- 5Use it as a rough guide and talk to a professional for real advice.
Common uses
- →Getting a quick sense of your weight status relative to your height.
- →Tracking BMI over time as part of a fitness goal.
- →Understanding where a BMI figure sits on the standard scale.
- →Comparing metric and imperial measurements.
- →Preparing information before a health check-up.
Tips & good to know
- BMI doesn't distinguish muscle from fat, so very athletic people can read as 'overweight' while being healthy.
- It's a population-level screening tool, not a diagnosis — always consult a doctor for personal advice.
- BMI categories are for adults; children and teens use age- and sex-specific charts.
Frequently asked questions
- How is BMI calculated?
- BMI is your weight in kilograms divided by the square of your height in metres. The calculator handles the maths and unit conversions for you.
- Is BMI accurate for everyone?
- No. It's a rough screening tool that ignores muscle mass, body composition and age, so treat it as a general guide only.
- Is my health data stored?
- No. The calculation runs in your browser and nothing is saved or uploaded.