What is the BMI Calculator?
The bmi calculator is a free online tool that helps you work out bmi quickly and accurately. It uses the standard formula BMI = weight(kg) / height(m)^2 and shows the result instantly as you type, along with a full breakdown so you can see exactly how the answer was reached.
How to use this calculator
- Enter your weight in kilograms.
- Enter your height in centimetres.
- Read your BMI and category.
Formula used
BMI = weight(kg) / height(m)^2Explanation of each input
- Weight (kg) โ the weight used in the calculation.
- Height (cm) โ the height used in the calculation.
Understanding your result
- BMI โ the calculated bmi.
Step-by-step calculation
For the example values 70 kg, 170 cm:
- Apply the formula:
BMI = weight(kg) / height(m)^2 - Substitute the values: 70 / 1.70^2
- Result: BMI = 24.2 (Normal)
Worked example
| Inputs | 70 kg, 170 cm |
|---|---|
| Working | 70 / 1.70^2 |
| Result | BMI = 24.2 (Normal) |
Benefits and practical uses
This calculator saves you time and reduces errors when you need bmi. It is useful for students, professionals and anyone who wants a fast, reliable answer without manual calculation. Results update instantly, work in your browser and can be copied or shared in one click.
Assumptions and limitations
- Adult BMI categories (WHO).
- Not valid for children, pregnancy or athletes.
Frequently asked questions
What is a healthy BMI?
For adults, 18.5-24.9 is considered normal. Below 18.5 is underweight and 25+ is overweight.
Is BMI accurate for everyone?
BMI does not distinguish muscle from fat, so it can misclassify athletes and the elderly. Use it as a general screen.