Maxi Calculator

BMI Calculator

BMI Calculator

Calculate your Body Mass Index (BMI) and see an adult screening category. This result does not assess your overall health.

Choose your preferred unit system

Enter your height in centimeters

Enter your weight in kilograms

Table of Contents

What is BMI?

Body Mass Index (BMI) is a calculation based on weight and height. For adults, it divides weight in kilograms by height in metres squared and can be used to screen for weight categories.

BMI alone does not establish whether a person is healthy. The adult category is one piece of information to discuss alongside other health factors.

BMI Ranges and Categories

For adults, BMI ranges are interpreted as follows:

  • Below 18.5 - Underweight
  • 18.5 to less than 25 - Normal weight
  • 25 to less than 30 - Overweight
  • 30 or greater - Obese

These are the adult categories for ages 20 and older in the CDC Adult BMI Categories guidance dated March 19, 2024. The date describes the source, not a change to your result.

How to Use the Calculator

  1. Select your preferred unit system (Metric or Imperial)
  2. Enter your height (in centimeters or inches)
  3. Enter your weight (in kilograms or pounds)
  4. Click the "Calculate BMI" button to see your results

The calculator will display your BMI value and indicate which category you fall into using a color-coded system for easy interpretation.

Limitations of BMI

While BMI is useful as a general guide, it has some limitations:

For informational purposes only: This calculator divides weight by height squared and applies adult BMI categories. BMI is a screening measure, not a diagnosis or a substitute for professional medical advice. It cannot assess your health from height and weight alone. Children and teens need age- and sex-specific BMI interpretation rather than these adult categories. See the CDC adult BMI guidance (reviewed March 19, 2024) and the CDC child and teen guidance (June 17, 2024).

  • It doesn't account for muscle mass
  • It may not be suitable for athletes or bodybuilders
  • It doesn't consider age or gender
  • It may not be appropriate for elderly people
  • It doesn't measure body fat distribution

Frequently Asked Questions

How often should I check my BMI?

This calculator does not set a checking schedule. If you have questions about your BMI or changes in weight, discuss them with a healthcare professional.

Is BMI accurate for everyone?

BMI is a general screening tool but may not be accurate for athletes, elderly people, or during pregnancy. Consult a healthcare provider for a more comprehensive health assessment.

What should I do if my BMI is outside the healthy range?

If your BMI falls outside the adult range of 18.5 to less than 25, consider consulting a healthcare provider or registered dietitian for personalized advice on achieving a healthy weight.