Glossary: QR Code Terms
- Module
- The smallest square unit in the QR grid.
- Quiet zone
- The white margin around the code; keep at least four modules of clear space.
- Error correction (ECC)
- Redundancy that allows recovery from damage. Levels: L, M, Q, H.
- Finder pattern
- The large corner squares used by scanners to locate and orient the code.
- Alignment pattern
- Smaller squares in larger versions that help correct geometric distortion.
- Version
- The grid size (modules per side), starting at 21×21 for Version 1.
- DPI
- Dots per inch for raster images. Vector SVG ignores DPI and scales cleanly.
- Vector vs raster
- Vector (SVG) scales without quality loss; raster (PNG) uses pixels and can blur when scaled.