How QR codes work
A practical overview so you can generate codes that scan reliably.
Key concepts
QR codes store data in a grid of dark and light modules. Scanners detect patterns, correct errors, and decode the payload.
How data is encoded
A QR code can store a URL, plain text, contact info, or formats like mailto: and tel:. Longer data usually increases density, which can reduce scan reliability at small sizes.
Finder patterns and alignment
The large corner squares help scanners detect orientation. Alignment patterns improve accuracy for larger codes or when scanning at an angle.
Error correction
Error correction lets scanners recover the payload if part of the code is damaged or covered. Levels are L, M, Q, and H. Higher levels improve resilience but increase density.
Quiet zone (margin)
The quiet zone is the empty border around the code. It helps scanners detect the QR code against surrounding content. If scans fail, increase the margin and keep nearby graphics away from the code.
Styling guidelines
- Keep contrast high: dark modules on a light background.
- Avoid non-uniform scaling or distortion.
- If you add a logo, keep it small and use higher error correction.
- Test on multiple devices before printing.
Want to generate a code now? Go back to Home. Want logos and shapes? Use Advanced.