QR Code Generator
Generate QR codes for URLs, text, email, phone, WiFi, and contacts. Customize and download as PNG.
What is a QR Code Generator?
A QR code generator creates two-dimensional barcodes that encode data in a matrix of dark and light modules. QR codes can store URLs, plain text, contact information, WiFi credentials, and more. This tool generates QR codes entirely in your browser — no data is sent to any server, ensuring complete privacy.
Understanding QR Code Structure
Every QR code contains several key components: finder patterns (the three large squares in the corners) for orientation detection, alignment patterns for distortion correction, timing patterns to establish the grid, format information encoding the error correction level, and the data region containing the actual encoded information. The "version" of a QR code (1–40) determines its size, from 21×21 modules (version 1) to 177×177 modules (version 40).
Error Correction Levels Explained
QR codes use Reed-Solomon error correction to remain scannable even when partially damaged. There are four levels:
- L (Low): ~7% of data can be restored. Smallest code size, best for clean environments.
- M (Medium): ~15% recovery. Good balance for most uses — the default choice.
- Q (Quartile): ~25% recovery. Recommended for printed materials that may get worn.
- H (High): ~30% recovery. Best for harsh environments or when adding a logo overlay.
Best Practices for QR Codes
Keep the data short — shorter data means fewer modules and easier scanning. Use high contrast colors (dark foreground, light background). Never invert colors. For print, ensure the QR code is at least 2 cm × 2 cm. Test the code with multiple scanner apps before distributing. Use error correction level M or higher for printed materials.
Frequently Asked Questions
What is a QR code?
A QR (Quick Response) code is a 2D barcode that stores data in a grid of black and white squares. Invented in 1994, it can be scanned by any smartphone camera to quickly access URLs, contacts, and more.
What are error correction levels?
QR codes have four levels: L (7% recovery), M (15%), Q (25%), and H (30%). Higher levels make codes readable even when partially damaged, but increase density.
What data types can QR codes encode?
QR codes can encode URLs, plain text, email addresses, phone numbers, WiFi credentials, vCard contacts, SMS messages, calendar events, and geographic coordinates.
How far away can a QR code be scanned?
Scan distance is roughly 10× the code's width. A 2.5 cm code scans from ~25 cm away; a 30 cm code from ~3 meters.
Can I customize QR code colors?
Yes, but maintain high contrast between foreground and background. Dark on light works best. Avoid inverted or low-contrast colors as many scanners won't read them.
Related Tools
- Color Contrast Checker — Check WCAG contrast compliance for your QR code colors.