Understanding how QR code size, version, and error correction level affect scannability and design choices.
QR codes come in 40 versions (sizes). Version 1 is the smallest at 21 x 21 modules, and Version 40 is the largest at 177 x 177 modules. Each version adds 4 modules per side. The version needed depends on how much data you are encoding and the error correction level chosen. Most everyday QR codes use Versions 1 through 6 (21 x 21 to 41 x 41 modules).
For reliable scanning, the physical size of your QR code matters. The general rule: the scanning distance should be no more than 10 times the QR code width. For a standard Version 2 QR code (25 x 25 modules), the minimum recommended printed sizes are:
Error correction allows a QR code to be read even when partially damaged or obscured. Higher error correction means more redundant data, which makes the QR code denser (more modules). Choose the level based on your use case:
| Level | Recovery | Best For |
|---|---|---|
| L (Low) | 7% | Clean environments, maximum data capacity |
| M (Medium) | 15% | General use, standard default |
| Q (Quartile) | 25% | Printed materials, outdoor use |
| H (High) | 30% | Adding logos, harsh environments |
Higher error correction reduces the amount of data you can store. For example, a Version 10 QR code can hold 174 alphanumeric characters at Level L, but only 62 at Level H. When creating QR codes with logos in the centre, always use Level H to ensure the code remains scannable even with the obscured area.
Related: How QR Codes Work | QR Codes for Business | URL QR Code