What is a BMI Calculator?
The Calnovix BMI Calculator helps you estimate body mass index quickly using standard adult formulas. Enter height and weight, choose metric or imperial units, and get an instant BMI value with a clear weight category.
Formula
BMI is calculated as weight (kg) divided by height (m) squared. Imperial values are converted to kilograms and centimeters first, then to meters, so the same WHO category thresholds apply for both unit systems. Category cut-offs follow the World Health Organization adult BMI classification (see Sources below).
How it works
- Choose Metric (kg/cm) or Imperial (lb/ft + in).
- Enter your current weight.
- Enter your height.
- Review your BMI and category in the results panel.
- Compare your result with the standard adult ranges shown below the score.
Worked examples
Average adult (metric)
A person who weighs 70 kg and is 170 cm tall.
BMI ≈ 24.2 → Normal
Imperial example
Someone who weighs 180 lb and is 5 ft 10 in tall.
BMI ≈ 25.8 → Overweight
Professional tips
- Measure height without shoes and weigh yourself at a consistent time of day.
- BMI is a screening tool — talk with a clinician for personalized advice.
- Track trends over time rather than focusing on a single reading.