What size should a QR code be for print?

Almost every QR code that fails in the wild is too small. Not broken, not badly designed. Just smaller than the distance it has to work across. The good news is the rule is arithmetic.

The 10:1 rule

The code should be roughly one tenth of the scanning distance.

Scanned from 1 metre, make it 10 cm. From 5 metres, 50 cm. That is the whole rule and it is close enough for almost every job.

The numbers

Those are minimums. Going bigger costs you nothing but layout.

The floor: 2 cm

Below about 2 cm, printing gets unreliable regardless of the maths. Ink spreads, modules bleed into each other, and cheap cameras cannot resolve the grid. If your design demands something smaller than 2 cm, do not shrink the code. Reduce what is in it instead.

Where the rule breaks: density

The 10:1 rule assumes a normal amount of data. Cram in a 300 character URL and the grid gets much finer, so every module gets smaller at the same physical size, and it stops scanning long before the rule says it should.

Two fixes:

• Shorten the content. Drop the UTM soup. site.com/menu beats site.com/pages/menu?utm_source=...
• Use a dynamic code. The pattern only ever holds a short redirect, so it stays coarse and scannable no matter how ugly the real destination URL is. Your tracking parameters live on the server side instead.

Versions explained covers the density maths if you want it.

Do not forget the quiet zone

Your 5 cm code needs blank space around it, four modules' worth on every side. That is part of the code, not a margin you can crop for a tighter layout. Budget the space before the designer does.

Print at vector, always

Download SVG for anything a printer touches. A PNG scaled up to poster size gets soft edges, and soft edges are exactly what a scanner struggles with. SVG is resolution independent, so a 2 metre billboard is as crisp as a business card. The studio exports SVG on the free tier.

The check that ends the argument

Print it at final size. Tape it where it will live. Walk to where people will actually stand. Scan it with an old phone. If that works, you are done, and if it does not, go up a size. It costs five minutes and it is the only test that counts.