QR Code
The dominant 2D matrix barcode: up to 7,089 digits in a square symbol with selectable error correction.
QR Code Specification
| Character set | Four modes: numeric (0-9), alphanumeric (45 chars), byte (ISO-8859-1 / UTF-8), and kanji/kana |
| Data length | Up to 7,089 numeric / 4,296 alphanumeric / 2,953 bytes / 1,817 kanji characters (version 40-L) |
| Check digit | No check digit; integrity via Reed-Solomon error correction (levels L/M/Q/H) |
| Density | Up to ~29,000 bits per symbol at version 40 — the densest common 2D code after Data Matrix |
| Module width (X-dimension) | 0.30-0.60 mm typical printed size; ≥0.4 mm recommended for phone scanning |
| Print ratio | Square grid of uniform modules |
| Magnification | Version 1 (21×21) at 0.5 mm is the common minimum for reliable mobile scanning |
| Quiet zone | 4 modules on all sides |
| Standard | ISO/IEC 18004 (originally Denso Wave AIM specification) |
| Origin | Masahiro Hara, Denso Wave, 1994 |
| Sample data | https://www.barcodegen.net |
Try It: Generate a QR Code Barcode
This live generator is preconfigured for QR Code. Adjust size, colors, and text — then download as PNG or SVG. Free, no signup, all encoding happens in your browser.
What Is QR Code?
QR Code (Quick Response Code) is a 2D matrix symbology standardized as ISO/IEC 18004. Data is encoded in square modules arranged on a grid from 21×21 (version 1) to 177×177 (version 40) modules, located by three large square finder patterns in the corners. Unlike 1D barcodes it is read in two dimensions by image sensors — phone cameras included — which is precisely why it conquered consumer use: no dedicated scanner hardware required.
QR Code packs up to 7,089 numeric digits, 4,296 alphanumeric characters, or 2,953 bytes in the largest version, and offers four Reed-Solomon error correction levels (L 7%, M 15%, Q 25%, H 30% of codewords recoverable). Higher correction survives damage and print defects but costs capacity. The standard also defines structured append (splitting data across symbols), Micro QR variants, and (in later revisions) rectangular frame-shaped symbols. Payments, tickets, Wi-Fi sharing, product authentication, and URL short-linking all run on QR today.
Common Applications
- Mobile payments and ticketing
- Marketing links, vCards, and Wi-Fi configuration
- Product authentication and traceability
- Boarding passes and event access control
Related Barcode Types
A compact 2D matrix code with fixed Reed-Solomon error correction — the standard for pharma serialization and tiny parts.
A compact matrix code with a bullseye finder and no quiet zone — popular on rail tickets.
A stacked-linear 2D code carrying up to 1,850 text characters — the workhorse of IDs, boarding passes, and transport documents.
QR Code FAQ
Which QR error correction level should I choose?
Default M (15%) suits clean printed labels. Use Q or H when the code will be worn, partially obscured by packaging curvature, or decorated with a logo overlay — H tolerates a logo covering up to 30% of the code. Use L only when you need maximum capacity and the print environment is controlled.
How much data fits in a QR Code?
It depends on mode and error correction. Digits are cheapest (7,089 max), then uppercase alphanumeric (4,296), then bytes (2,953). A typical URL of 50-100 characters fits comfortably in versions 4-6 — small codes that scan instantly from phone cameras.
Why does my QR Code have a different pattern for the same data?
QR masks (the XOR patterns applied to the data region) are chosen by the encoder to avoid confusing dark-module runs; different libraries with different mask heuristics can pick different masks, and any change in version, correction level, or encoding mode also changes the pattern. All valid renderings decode to the same data.