What Is a QR Code and How Does It Work?
Direct Answer
A QR code (Quick Response code) is a two-dimensional barcode that stores data — like a website link, WiFi password, or contact card — as a scannable pattern of black-and-white squares, readable instantly by any smartphone camera.
Key Facts
- ✓Invented 1994 by Denso Wave (Japan) for automotive parts tracking
- ✓Can store up to 4,296 alphanumeric characters
- ✓Readable in any direction — still scannable even if up to 30% damaged, thanks to error correction
- ✓No app needed — every modern smartphone camera scans natively
Full Explanation
A QR code encodes data into a grid of black squares on a white background. Three large squares in the corners let a scanner instantly recognise orientation and position; the rest of the grid decodes into the underlying data (usually a URL, but also plain text, WiFi credentials, or a vCard). Unlike a 1D barcode, which only stores data horizontally, a QR code stores data both horizontally and vertically, holding vastly more information in the same space.
Related Questions
What's the difference between a QR code and a barcode?
A barcode stores data in one dimension and typically holds only a short numeric code. A QR code stores data in two dimensions (a grid), letting it hold vastly more information — a full URL, contact card, or WiFi password instead of just a product number.
How many characters can a QR code hold?
Up to 4,296 alphanumeric characters, 7,089 numeric-only digits, or 2,953 bytes of binary data — though for reliable scanning it's best to keep content well under that.
Do I need an app to scan a QR code?
No. Every modern iPhone (iOS 11+) and Android phone (Android 9+) scans QR codes natively using the built-in Camera app — no separate scanner app is required.
Related Resources
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