BMI Calculator

Enter your height and weight to get your BMI and the standard category — underweight, healthy, overweight or obese.

All calculations happen in your browser.

How to use BMI Calculator

  1. Choose metric (kg / cm) or imperial (lb / ft+in).
  2. Enter your height and weight.
  3. Your BMI and category update instantly.

About this tool

Body Mass Index is a simple measure of weight relative to height, used by health professionals as a quick screening tool. The calculator follows the standard World Health Organization categories.

BMI is a general guide, not a diagnosis — it does not distinguish muscle from fat, and it does not apply the same way to children, older adults, athletes or during pregnancy.

When to use it: a quick adult health screening alongside other measures.

Frequently asked questions

What are the BMI categories?
Below 18.5 is underweight, 18.5–24.9 is healthy, 25–29.9 is overweight, and 30 or above is obese. These are the standard WHO ranges for adults.
Is BMI accurate for everyone?
No. It is a rough screening tool and does not account for muscle mass, age, sex or body composition. Talk to a health professional for a full assessment.
What are the BMI categories?
For adults, the common ranges are: under 18.5 underweight, 18.5–24.9 healthy range, 25–29.9 overweight, and 30+ obesity.
Does BMI work for athletes?
Use caution — muscle is denser than fat, so muscular people can score “overweight” while lean. Treat BMI as a screen, not a diagnosis.
Is it valid for children?
No — children and teens are assessed with age- and sex-specific growth percentiles. This calculator is for adults.
Are my measurements stored?
No — everything is computed in your browser and nothing is saved or sent.

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How to use Bmi Calculator

Enter the required values into the Bmi Calculator fields. The calculation updates as you adjust inputs. Use the result for planning, comparison, or documentation.

Practical benefits

Frequently asked questions

Is this tool free to use?
Yes. Bmi Calculator is fully free with no account or subscription required.
Does it upload my files?
No. All processing occurs locally within your browser session.
Can I use this for professional projects?
Yes, the tool is designed for both casual and professional use. Always verify critical outputs.