What Is a QR Code and How Does It Work?

QR codes are everywhere — on restaurant menus, product packaging, business cards, and even tombstones. But how do these little square patterns actually work? Let's break it down.

What does QR stand for?

QR stands for "Quick Response." It was invented in 1994 by Denso Wave, a Japanese subsidiary of Toyota, to track vehicles and parts during manufacturing. The format was designed to be read quickly — hence the name.

How does a QR code work?

A QR code is a two-dimensional barcode that encodes data in a grid of black and white squares. Unlike traditional barcodes that store data in one direction, QR codes store data both horizontally and vertically — allowing them to hold much more information.

QR code structure

• Finder patterns: The three large squares in the corners that help scanners locate the code
• Alignment pattern: A smaller square that helps correct for distortion
• Timing patterns: Alternating黑白 rows/columns that help determine the grid size
• Data modules: The actual encoded data in the remaining squares
• Error correction: Redundant data that allows the code to be read even if partially damaged

What can QR codes store?

• URLs and web links
• Contact information (vCard)
• Plain text messages
• Wi-Fi network credentials
• Email addresses and phone numbers
• Payment information

Error correction levels

QR codes have four error correction levels: L (7%), M (15%), Q (25%), and H (30%). Higher levels allow the code to be read even if up to 30% of it is damaged or obscured. This is why you can sometimes add a logo to the center of a QR code and it still works.

How to create your own QR code

You can generate QR codes for free using browser-based tools. Simply enter the text or URL you want to encode, customize the colors and size, and download the QR code as PNG or SVG. No software installation needed.