How QR Codes Work: The Technology Behind the Squares
Understand the magic behind QR codes: how they store data, their error correction, and why they are so useful today.
Table of Contents
We see them everywhere: restaurant menus, movie tickets, and even TV commercials. But have you ever wondered how those strange black and white squares store information?
A Bit of History
The QR (Quick Response) code was invented in 1994 by Denso Wave, a Toyota subsidiary. It was originally designed to track vehicles during high-speed manufacturing. Unlike traditional barcodes that only store data horizontally, QR codes are two-dimensional, meaning they store info both vertically and horizontally.
How Much Data Can They Store?
Much more than a barcode! While a standard barcode holds about 20 digits, a QR code can handle:
- Up to 7,089 numeric characters.
- Up to 4,296 alphanumeric characters.
- Up to 2,953 bytes of binary data.
Error Correction: The Magic Feature
One of the coolest features is their ability to remain readable even if damaged or dirty. This is thanks to Reed-Solomon Error Correction.
There are four levels of redundancy:
- Level L (Low): Recovers 7% of data.
- Level M (Medium): Recovers 15% of data.
- Level Q (Quartile): Recovers 25% of data.
- Level H (High): Recovers 30% of data.
That’s why you can put a logo in the middle of a QR code (like our tool does) and it still works: the scanner “reconstructs” the missing info using the redundant data.
Create Your Own QR
Want to try it out? You can use our Free QR Code Generator to create one right now, customize colors, and add your own logo.