Free BMI Calculator
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About the BMI Calculator
Calculate your Body Mass Index from your height and weight in metric or imperial units — see your BMI category and healthy weight range, all in your browser.
How to use the BMI Calculator
- 1Choose metric (kg, cm) or imperial (lb, ft/in) units.
- 2Enter your height and weight.
- 3See your BMI, its category and the healthy weight range for your height.
- 4Everything is calculated in your browser — nothing is uploaded.
Frequently asked questions
Is this BMI calculator free?
Yes — completely free, with no sign-up and no watermark.
Is my data uploaded anywhere?
No. Your height and weight are used only in your browser — nothing is sent anywhere.
What is BMI?
Body Mass Index is a simple measure of body weight relative to height, calculated as weight in kilograms divided by height in metres squared. It's used as a quick screening indicator for weight categories.
What are the BMI categories?
For adults: below 18.5 is underweight, 18.5–24.9 is a normal (healthy) weight, 25–29.9 is overweight, and 30 or above is obese.
Is BMI accurate for everyone?
No — BMI doesn't distinguish muscle from fat or account for age, sex or body composition, so it can be misleading for athletes, older adults and others. Treat it as a rough guide and talk to a healthcare professional for a proper assessment.