BMI Calculator
Calculate Body Mass Index and see the WHO category for your height and weight.
How to use this tool
- Choose metric or imperial.
- Enter height and weight.
- Click Calculate for BMI, category and a simple chart.
How it works
Weight divided by height squared (kg/m²), converted to the same metric for imperial inputs, then matched to categories.
Tips
- Track BMI trends over months, not single readings.
- Combine with waist measurement for a better health signal.
- Children's BMI uses age-and-sex percentiles — adult categories don't apply.
Limitations
A screening index only; it doesn't assess body fat percentage or distribution.
Frequently asked questions
How is BMI calculated?
BMI = weight (kg) / height (m) squared, or 703 x weight (lb) / height (in) squared for imperial.
What are the BMI categories?
Underweight <18.5, normal 18.5-24.9, overweight 25-29.9, obese 30 and above (WHO standard).
Is BMI accurate for athletes?
BMI doesn't distinguish muscle from fat, so muscular people can score 'overweight'. Use it as a screening number, not a verdict.