BMI Calculator
Body mass index from your height and weight — metric or imperial — with your category and healthy range.
BMI is a general screening measure, not medical advice — it can misread muscular or older bodies. Talk to a healthcare professional about what your number means for you.
About this tool
Body mass index (BMI) is the standard quick screen for weight relative to height: weight in kilograms divided by height in metres squared. Enter your numbers in metric or imperial and this calculator shows your BMI instantly, the WHO category it falls in, and the healthy weight range for your exact height — often the most useful number on the page.
How to calculate your BMI
- Pick your units — metric or imperial.
- Enter height and weight; the result appears instantly.
- Check the category and the healthy range for your height.
Frequently asked questions
How is BMI calculated?
BMI is weight in kilograms divided by height in metres squared (kg/m²). In imperial units the equivalent formula is 703 × weight in pounds ÷ height in inches squared. This calculator applies the right formula automatically.
What do the BMI categories mean?
The WHO ranges for adults are: under 18.5 underweight, 18.5–24.9 healthy weight, 25–29.9 overweight, and 30 or above obesity. The calculator shows where your number falls and the weight range that maps to 18.5–24.9 for your height.
Is BMI accurate for everyone?
No — BMI is a population-level screening measure, not a diagnosis. It doesn't distinguish muscle from fat, so athletes can score high while lean, and it applies differently to children, pregnant women and the elderly. Treat it as a rough indicator and talk to a healthcare professional about what it means for you.
Is my data stored or sent anywhere?
No. The calculation runs entirely in your browser — nothing you type is transmitted or saved.