Make your QR code smaller and easier to scan

A QR code stores its content in the grid of black and white squares called modules. The standard defines 40 sizes, from 21×21 up to 177×177 modules: the more characters you encode, the bigger the grid the code has to use.

The two codes above point to the same product page. The left one encodes the full 137-character URL, tracking parameters included, and needs a 49×49 grid. The right one encodes a 23-character short link and fits in 25×25: fewer than half the modules along each edge, and each module nearly twice as large at the same print size.

You cannot compress a URL inside the QR standard, but you can shorten what the code has to store: that is the whole trick, and it is what a URL shortener does.

Scanners need each module to cover enough pixels in the camera image. A common rule of thumb: a QR code scans reliably from about ten times its own width, and each module should print at least 0.4mm wide. Both rules favor codes with fewer modules.

In practice that means a simpler code can print smaller on a business card, or scan from farther away on a poster, and it survives glossy paper, curved surfaces, and cheap printers with far more grace.

QR codes carry redundancy so they still scan when partly covered or damaged. A logo in the middle spends part of that budget, and a dense code has less to spare. A shorter URL keeps the grid coarse and the redundancy intact, which is exactly what you want before placing a logo on top.