QR Code Generator

QR Code Generator: Everything You Need to Know

QR (Quick Response) codes are two-dimensional barcodes that store information in a grid of black and white squares. Originally developed in 1994 by Denso Wave for tracking automotive parts, QR codes have become ubiquitous in marketing, payments, authentication, and everyday information sharing.

How QR Codes Work

A QR code encodes data as a pattern of dark and light modules arranged in a square grid. The code includes finder patterns (the three large squares in the corners) that help scanners detect and orient the code, alignment patterns for distortion correction, timing patterns for coordinate mapping, and the actual data payload encoded using Reed-Solomon error correction.

Error Correction Levels

• L (Low, ~7%): Minimal redundancy. Produces the smallest, simplest code. Best for clean digital displays.
• M (Medium, ~15%): The default choice. Good balance between size and reliability for most use cases.
• Q (Quartile, ~25%): Higher redundancy. Suitable when codes may be partially obscured or printed on uneven surfaces.
• H (High, ~30%): Maximum redundancy. Allows up to 30% of the code to be damaged while remaining scannable. Required if you place a logo over the center of the QR code.

Best Practices for QR Codes

• Sizing: For printed materials, the minimum recommended size is 2 cm x 2 cm (about 0.8 inches). For scanning at a distance, use the rule: scanning distance / 10 = minimum QR code size.
• Contrast: Maintain high contrast between foreground and background colors. Dark modules on a light background works best. Avoid low-contrast or inverted color schemes.
• Quiet zone: Always leave a margin (quiet zone) of at least 4 modules around the QR code to ensure scanners can detect the boundaries.
• Testing: Always test your QR code with multiple scanner apps and devices before printing or distributing.

Common Use Cases

• URLs: Link to websites, landing pages, app download pages, or social media profiles.
• Wi-Fi: Encode network credentials so guests can connect by scanning (format: WIFI:T:WPA;S:NetworkName;P:Password;;).
• vCards: Share contact information that can be directly saved to a phone's address book.
• Payments: Mobile payment systems use QR codes for peer-to-peer and point-of-sale transactions.
• Authentication: Two-factor authentication apps use QR codes to exchange TOTP secrets during setup.