How versions are numbered
The version number sets the grid size. The side length in modules is 17 plus 4 times the version, so version 1 is 21 × 21, version 2 is 25 × 25, and version 40 is 177 × 177.
The version is about module count, not physical size. A version 2 code can be printed as large as a billboard or as small as a postage stamp; what changes with the version is how much data fits and how fine the modules are.
- Version 1: 21 × 21 modules
- Version 2: 25 × 25 modules
- Version 10: 57 × 57 modules
- Version 25: 117 × 117 modules
- Version 40: 177 × 177 modules
- Micro QR M1 to M4: 11 × 11 to 17 × 17 modules
How the version is chosen
Most generators pick the smallest version that holds the data at the chosen error correction level. Longer content, a less efficient encoding mode or a higher error correction level all push the code to a larger version.
A higher version means more, smaller modules at the same printed size, so it needs a sharper print and a closer or better camera. Keeping content short, for example by using a short link, keeps the version low and the code easy to scan.
Structural changes by version
The version also decides which fixed patterns appear. Version 1 has no alignment pattern, versions 2 and up have one or more, and versions 7 and up carry version information blocks beside two of the finder patterns.