Glossary
Version information
Version information is an 18-bit block present only in QR codes of version 7 and above, recording the code's size. Smaller codes do not need it because the decoder can count modules directly.
View as MarkdownPaste this page into any AI assistant. It is plain, portable Markdown.
Structure
6 data bits for the version number plus 12 Golay error-correction bits, stored twice, once near the top-right finder pattern and once near the bottom-left.
Why only version 7 and up
For a small code, counting the modules between finder patterns is unambiguous. As codes get larger, accumulated sampling error makes a miscount plausible, so the version is stated explicitly.
The threshold at version 7 (45 × 45 modules) is a spec decision, not a physical boundary.
Related
- Version, A QR code's version is its size: version 1 is 21 × 21 modules and each step adds 4 modules per side, up to version 40 at 177 × 177. The encoder picks the…
- Format information, Format information is the 15-bit block next to the finder patterns that records the error-correction level and mask pattern. It is stored twice and…
- Module, A module is one square cell of a QR code: the smallest unit of the pattern. Codes are measured in modules, not pixels or millimetres, because the module…