How to Calculate BMI Accurately: A Complete Guide

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 meters squared.

How to Calculate Your BMI

To calculate your BMI manually:

1. Measure your weight in kilograms
2. Measure your height in meters
3. Square your height (multiply it by itself)
4. Divide your weight by your squared height

Understanding BMI Categories

• Underweight: BMI less than 18.5
• Normal weight: BMI 18.5 to 24.9
• Overweight: BMI 25 to 29.9
• Obese: BMI 30 or greater

Limitations of BMI

While BMI is a useful screening tool, it has limitations. It doesn't distinguish between muscle and fat mass, so athletes and very muscular individuals may have high BMI despite being healthy. It also doesn't account for age, gender, or body composition.

Use Our Free BMI Calculator

Skip the manual calculation and use our free BMI calculator for instant, accurate results. Simply enter your height and weight, and get your BMI category immediately.