# BMI Calculator

Your body mass index in two seconds, with the WHO ranges.

URL: https://shortformkit.com/bmi-calculator/
Updated: 2026-10-13

BMI compares weight with height. It is a quick screening number for adults, not a diagnosis: it does not know how much of your weight is muscle, so athletes often get a high BMI while being lean.

**Formula:** BMI = weight in kg ÷ (height in m)²

Results are estimates for general information, not medical or financial advice.

## How it works

1. **Enter your values** The result updates as you type.
2. **Switch units if needed** Metric or US units, where it applies.
3. **Read the result** Nothing is stored or sent anywhere.

## FAQ

**Is BMI accurate for athletes?**
Not very. Muscle is heavier than fat, so strong or very fit people often land in the overweight range. The body fat calculator gives a better picture.

**Is it free?**
Yes. No account, no limits.

**Is my data stored?**
No. The calculation happens in your browser and nothing is sent to a server.


Source: Shortform Kit (https://shortformkit.com/bmi-calculator/). Free, no login.