What is QR Code?
QR Code (Quick Response Code) is a two-dimensional matrix barcode that can store various types of data including URLs, text, contact information, and more. It was invented in 1994 by Denso Wave for tracking automotive parts and has since become ubiquitous for mobile scanning applications.
Quick Facts
| Full Name | Quick Response Code |
|---|---|
| Created | 1994 by Denso Wave (Masahiro Hara) |
| Specification | Official Specification |
How It Works
QR codes consist of black squares arranged on a white background in a square grid pattern. They include three distinctive square patterns in the corners for alignment and can store up to 7,089 numeric characters or 4,296 alphanumeric characters. QR codes feature built-in error correction using Reed-Solomon codes, allowing them to remain readable even when partially damaged. They can be scanned from any angle and are widely used for payments, authentication, marketing, and information sharing. Dynamic QR codes use short URLs that redirect to the actual destination, allowing the target to be changed after printing. Security risks include QR code phishing (quishing) where malicious codes redirect to fake websites. Best practices: verify the URL before visiting, use QR scanners that preview URLs, and be cautious of codes in public places.
Key Characteristics
- Two-dimensional barcode readable from any orientation
- Supports multiple data types: numeric, alphanumeric, binary, kanji
- Built-in error correction (L, M, Q, H levels)
- High data density compared to traditional barcodes
- Three finder patterns for quick detection and alignment
- Supports various sizes from 21x21 to 177x177 modules
Common Use Cases
- Mobile payment systems (WeChat Pay, Alipay)
- URL sharing and website links
- Contact information exchange (vCard)
- Product tracking and inventory management
- Event tickets and boarding passes
Example
Loading code...Frequently Asked Questions
What is the maximum data capacity of a QR code?
A QR code can store up to 7,089 numeric characters, 4,296 alphanumeric characters, 2,953 bytes of binary data, or 1,817 kanji characters. The actual capacity depends on the error correction level used.
What are the different error correction levels in QR codes?
QR codes have four error correction levels: L (Low, ~7% recovery), M (Medium, ~15% recovery), Q (Quartile, ~25% recovery), and H (High, ~30% recovery). Higher levels allow more damage tolerance but reduce data capacity.
Can QR codes be scanned if partially damaged?
Yes, QR codes use Reed-Solomon error correction, allowing them to be read even when partially damaged or obscured. Depending on the error correction level, up to 30% of the code can be damaged while remaining scannable.
What is the difference between static and dynamic QR codes?
Static QR codes encode data directly and cannot be changed after creation. Dynamic QR codes contain a short URL that redirects to the actual content, allowing you to change the destination without reprinting the code.
Are QR codes secure?
QR codes themselves are not inherently secure or insecure. However, they can be exploited for phishing attacks (called 'quishing'). Always preview the URL before visiting, use trusted QR scanner apps, and be cautious of codes in public places.