BMI Calculator
Calculate Body Mass Index (BMI) from weight in kg and height in cm.
Loading tool…
Recommended next step
Continue with related tools
After using BMI Calculator, continue with BMR Calculator.
Continue this path
Tools selected to complete the same task.
Tool guide
BMI Calculator: how it works
Practical information to understand the result and use this tool correctly.
About BMI Calculator
BMI (body mass index) is weight in kilograms divided by height in meters squared: BMI = kg / m². If height is in cm, convert to meters first (divide by 100).
Example: 70 kg and 175 cm → 70 / 1.75² ≈ 22.9 (normal range for adults).
WHO adult ranges: under 18.5 underweight; 18.5–24.9 normal; 25–29.9 overweight; 30+ obesity. BMI is a screening number, not a full health diagnosis.
Use the interactive calculator above for an instant result, then compare it with the adult WHO table on the page.
How to use it
- 1Enter weight in kilograms.
- 2Enter height in centimeters.
- 3Read BMI and WHO category.
- 4Compare with the adult WHO table on the page.
Frequently asked questions
- How do I calculate BMI with kg and cm?
- BMI = kg ÷ (cm ÷ 100)². Example: 80 kg and 170 cm → 80 / 1.70² ≈ 27.7.
- What is a normal BMI?
- For most adults, WHO considers 18.5–24.9 a normal range. Values outside that range are only a screening signal.
- Is BMI the same for children?
- No. Children and teens need age- and sex-specific charts; adult cut-offs do not apply.
- Is this BMI calculator free?
- Yes. It runs in your browser with no account required.