🧮 Calculators & Daily Life

BMI Calculator

Enter your height and weight — your BMI (Body Mass Index), weight category and an ideal-weight estimate appear right away. A simple health reference. Everything stays in your browser.

Examples (click to try):

How to Use the BMI Calculator

Enter your height and weight to instantly see your BMI (Body Mass Index), weight category, and an ideal-weight estimate. Use it as a quick reference for everyday health tracking.

  1. Enter your Height in centimeters (e.g. 170).
  2. Enter your Weight in kilograms (e.g. 65).
  3. The BMI, category, and ideal weight update as you type.

Click an example chip above the inputs (such as "170cm 65kg") to fill in the height and weight and see the BMI and category right away. Trying one first, then editing it to your own figures, is the quickest way to start.

BMI is calculated as weight (kg) divided by height (m) squared. The ideal weight shown is the weight at a BMI of 22 — height (m) squared times 22 — a commonly used reference point.

Worked example: for a height of 170cm and weight of 65kg, 170cm = 1.7m, so BMI = 65 ÷ (1.7 × 1.7) = 22.5 (Normal), and the ideal weight is 1.7 × 1.7 × 22 = 63.6kg.

Everything recalculates automatically as you type — no button to press. Handy when you want to compare several figures quickly.

When This Helps

  • Checking your BMI and category before or after a health check-up.
  • Using an ideal-weight target as a reference for fitness goals.
  • Comparing figures for the whole family in one place.

Weight Categories (WHO)

  • BMI under 18.5: Underweight
  • 18.5 to under 25: Normal
  • 25 to under 30: Overweight
  • 30 to under 35: Obese class I
  • 35 to under 40: Obese class II
  • 40 and above: Obese class III

Frequently Asked Questions

Is my height and weight sent to a server?
No. All BMI calculations happen entirely in your browser. The height and weight you enter are never transmitted to or stored on any external server. You can use this tool with complete confidence.
Which standard does the category use?
This English version uses the WHO (World Health Organization) classification: under 18.5 is Underweight, 18.5 to 25 is Normal, 25 to 30 is Overweight, and 30 and above is Obese (class I to III). Note that the Japanese version uses the Japan Society for the Study of Obesity criteria, which divide the higher range differently.
How is the ideal weight calculated?
The ideal weight shown is the weight at a BMI of 22, calculated as height (m) squared times 22 — a commonly used reference point. It is only an estimate, and the right weight varies with build and muscle mass.