How QR Codes Work
QR (Quick Response) codes are two-dimensional barcodes that encode data in a pattern of black and white squares. Invented by Denso Wave in 1994 for tracking automotive parts, they're now used everywhere — from restaurant menus to payment systems.
What You Can Encode in a QR Code
- URLs: Link to websites, landing pages, or app download pages
- Plain text: Up to ~4,296 alphanumeric characters
- Wi-Fi credentials:
WIFI:T:WPA;S:NetworkName;P:Password;; - vCard contacts: Full contact information that can be saved with one scan
- Email: Pre-compose an email:
mailto:user@example.com?subject=Hello - Phone number:
tel:+1234567890 - SMS:
smsto:+1234567890:Your message here - Geographic location:
geo:40.7128,-74.0060— opens in maps
QR Code Best Practices
- Size: Minimum 2cm x 2cm for print. Ensure adequate quiet zone (white border) around the code.
- Color: Dark foreground on light background. The foreground should be at least 40% darker than the background for reliable scanning.
- Error correction: Use higher error correction (H or Q level) if you plan to add a logo overlay — the code can still be read with up to 30% obscured.
- Testing: Always test your QR code with multiple devices and apps before printing.
- URL shortening: Shorter URLs create simpler QR codes with larger modules (the individual squares), making them easier to scan from a distance.
Static vs Dynamic QR Codes
Static: The data is encoded directly in the code. Cannot be changed after creation. This tool generates static QR codes — they work forever with no tracking or expiration.
Dynamic: The code points to a redirect URL that can be changed later. Requires a service to host the redirect. Useful for marketing campaigns where you want to track scans or update the destination.