BMI Calculator

Calculate Body Mass Index.

BMI Categories

UnderweightLess than 18.5
Normal weight18.5 - 24.9
Overweight25 - 29.9
Obesity30 or more

Understanding Your Body Mass Index (BMI)

A complete guide to understanding BMI, how it is calculated, and what your results actually mean for your health.

What is BMI?

Body Mass Index (BMI) is a simple calculation using a person's height and weight. The formula is BMI = kg/m² where kg is a person's weight in kilograms and m² is their height in metres squared. A BMI of 25.0 or more is overweight, while the healthy range is 18.5 to 24.9. BMI applies to most adults 18-65 years.

Why Use Our BMI Model?

Our BMI calculator provides instant, accurate results using the standard formula recognized by health organizations worldwide like the WHO and CDC. Unlike basic calculators, we offer:

  • Dual Unit Support: Seamlessly switch between Metric (kg/cm) and Imperial (lb/ft) units.
  • Instant Classification: Immediately see if you fall into Underweight, Normal, Overweight, or Obesity categories.
  • Privacy Focused: Your health data never leaves your browser.

The BMI Formula

The standard formulas used for calculating BMI are:

Metric Units

BMI = weight (kg) / [height (m)]²

Imperial Units

BMI = 703 × weight (lbs) / [height (in)]²

BMI Categories

  • Underweight: BMI is less than 18.5
  • Normal weight: BMI is 18.5 to 24.9
  • Overweight: BMI is 25 to 29.9
  • Obesity: BMI is 30 or more

Frequently Asked Questions