BMI Calculator

Calculate your Body Mass Index and health category.

How to Do It Manually

BMI (Body Mass Index) is calculated by dividing weight in kilograms by height in meters squared. It estimates body fat based on height and weight.

BMI = weight (kg) / [height (m)]² or BMI = [weight (lbs) / height (inches)²] × 703
  1. Measure your weight in kilograms (or convert from pounds: divide by 2.205).
  2. Measure your height in meters (or convert from inches: divide by 39.37).
  3. Square your height.
  4. Divide weight by height squared.

Frequently Asked Questions

What is a normal BMI range?

BMI under 18.5 is underweight, 18.5–24.9 is normal weight, 25–29.9 is overweight, and 30+ is obese.

Is BMI accurate for athletes?

BMI doesn't distinguish between muscle and fat. Athletes may have a high BMI despite low body fat.

What about children?

Children use age and sex-adjusted BMI percentiles, not the adult BMI categories.