QR Code Generator: Create QR Codes for Free
Learn how QR codes work, the different QR code versions and error correction levels, and how to generate QR codes for URLs, text, WiFi, and more.
What Is a QR Code?
A QR (Quick Response) code is a two-dimensional barcode that can store data both horizontally and vertically. Invented in 1994 by Denso Wave for tracking automotive parts in manufacturing, QR codes have become one of the most widely used data encoding formats in the world.
Unlike traditional barcodes that store data in a single row of lines, QR codes use a grid of black and white squares (called "modules") arranged in a square pattern. This two-dimensional structure allows them to store significantly more data β up to 7,089 numeric characters or 4,296 alphanumeric characters.
The distinctive three large squares in the corners of every QR code are called "finder patterns." They allow scanners to quickly identify and orient the code from any angle, which is why QR codes can be scanned even when held upside down or at an angle.
How QR Codes Work
QR codes have 40 different "versions" (sizes), ranging from Version 1 (21x21 modules) to Version 177 (177x177 modules). Each version can hold progressively more data. The most commonly used versions are:
| Version | Size | Alphanumeric Capacity |
|---|---|---|
| 1 | 21x21 | 25 characters |
| 2 | 25x25 | 47 characters |
| 5 | 37x37 | 134 characters |
| 10 | 57x57 | 305 characters |
| 20 | 97x97 | 858 characters |
The encoder automatically selects the smallest version that can hold your data. The data is encoded using Reed-Solomon error correction, which adds redundancy so the code can still be read even if partially damaged or obscured.
Error Correction Levels
QR codes support four error correction levels, each offering a different balance between data capacity and damage recovery:
| Level | Recovery Capacity | Best For |
|---|---|---|
| L (Low) | ~7% damage recovery | Maximum data capacity |
| M (Medium) | ~15% damage recovery | General use (default) |
| Q (Quartile) | ~25% damage recovery | Industrial environments |
| H (High) | ~30% damage recovery | When adding logos or artwork |
Common Uses for QR Codes
- URLs: Direct users to a website without typing. The most common QR code use case.
- WiFi credentials: Encode network name and password so guests can connect by scanning.
- Contact information (vCard): Share name, phone, email, and address in a single scan.
- Event details: Calendar events with date, time, location, and description.
- Payments: Mobile payment systems like WeChat Pay and Alipay use QR codes extensively.
- Product information: Link to manuals, reviews, or authentication verification.
QR Code Best Practices
- Minimum size: Print QR codes at least 2cm (0.8 inches) square for reliable scanning at arm's length.
- Quiet zone: Always leave a white margin (at least 4 modules wide) around the code.
- Test before printing: Always scan your QR code with multiple devices before mass printing.
- Use higher error correction for logos: If embedding a logo in the center, use Level H to ensure readability.
- Short URLs: For URL QR codes, use a URL shortener to reduce complexity and improve scan reliability.
Try it now: Open the QR Code Generator →
Generate free QR codes for URLs, text, WiFi, and more. Download as PNG or SVG.
Frequently Asked Questions
What is a QR code?
A QR (Quick Response) code is a two-dimensional barcode that can encode text, URLs, contact information, WiFi credentials, and more. It was invented in 1994 by Denso Wave for tracking automotive parts and is now widely used in marketing, payments, and information sharing.
How much data can a QR code hold?
A QR code can hold up to 7,089 numeric characters, 4,296 alphanumeric characters, or 2,953 bytes of binary data, depending on the version and error correction level.
Do QR codes expire?
QR codes themselves do not expire β they are static images. However, if a QR code points to a URL that becomes inactive, the QR code will still scan but the link will not work.