BMI Calculator

Last updated: July 4, 2026
Reviewed by Dr. Alana Reyes, MD

About this Calculator

Body Mass Index (BMI) is a simple, internationally recognized screening parameter used to estimate biological body fat based on a person’s height and weight. It is widely used by clinicians to evaluate body weight categories for adults.

Formula & Calculations

Mathematical Formula

BMI = Weight (kg) / [Height (m)]²
  • Weight: Measured in kilograms (kg) or pounds (lbs).
  • Height: Measured in meters (m) or inches (in).

How to Calculate Step-by-Step

1

Measure parameters

Gather height in meters and weight in kg.

2

Square height

Multiply height in meters by itself.

3

Divide

Divide weight in kilograms by the squared height value.

How to Use & Best Practices

Select your unit system (Metric or Imperial), input your age and gender, and then drag the sliders to see your BMI score instantly.

Frequently Asked Questions

Why doesn't BMI work well for athletes?

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BMI is unable to distinguish between dense muscle tissue and fatty tissue, occasionally categorizing bodybuilders as overweight.

What are the limitations of BMI?

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It ignores subcutaneous vs visceral fat levels and muscle percentage.

Dr. Alana Reyes, MD, MPH Clinical Reviewer

Dr. Reyes is a board-certified endocrinologist specializing in metabolic health and metabolic disorders.

Want to learn more about this calculator?

Ask our AI assistant for explanations, formulas, or usage advice.

Calculate BMI

years
Gender
Your BMI 22.9
Category Normal Weight
15.0 18.5 25.0 30.0 40.0
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