Health2026-06-01 - 2 min read

BMI Calculator — A Complete Guide to Body Mass Index

Body Mass Index (BMI) is a widely used, simple tool that estimates your body fat based on your height and weight. It is a quick way to screen for potential weight-related health issues.

The BMI Formula

BMI is calculated using the following mathematical formula:

BMI = Weight (kg) / [Height (m)]²

BMI Categories

Understanding where you fall on the spectrum can help you make informed decisions about your health and fitness goals:

BMI RangeCategory Below 18.5Underweight 18.5 – 24.9Healthy Weight ✓ 25.0 – 29.9Overweight 30.0 and AboveObese

A Practical Example

Let’s calculate the BMI for someone who weighs 70 kg and is 170 cm (1.70 m) tall:

Square the height: 1.70 × 1.70 = 2.89

Divide weight by height squared: 70 ÷ 2.89 = 24.2

Result: A BMI of 24.2 falls within the Healthy Weight category.

Interested in finding your own BMI? Try Our Free BMI Calculator

Disclaimer: BMI is a screening tool, not a diagnostic one. It does not measure body fat directly or account for muscle mass. Consult a healthcare professional for personalized medical advice.