What size to print a QR code

6 min read

The distance rule

The useful ratio is ten to one. A QR code can be scanned reliably from about ten times its own width. Turn that around and you get the size you need:

Treat these as minimums, then add margin. The ratio assumes a decent camera, good light, and someone holding still. A billboard beside a road meets none of those conditions.

Module size is the real limit

A QR code is a grid, and the grid square is called a module. For print, keep each module at or above about 0.4mm. Below that, ink spread on absorbent paper starts merging neighbouring modules and the code becomes unreadable no matter how good the camera is.

This is why content length decides print size. A code holding a short URL might be 25 modules across, so at 0.4mm per module it works down to about 10mm. Add a long tracking string and the same code might be 45 modules across, needing 18mm for the same module size. The code did not get more complicated to look at, but it got much harder to print small.

If a code has to be small, shorten what it encodes. That does more than any other change, and it is covered in more detail in the guide on error correction.

The quiet zone

A QR code needs an empty margin around it, called the quiet zone, and the specification asks for four modules on every side. It is not padding for looks. The scanner uses it to tell where the code ends.

Losing it is the most common print mistake. A code placed hard against a coloured panel, a photograph, a page edge, or a border rule can fail even though the code itself is perfect. When in doubt, give it more white space than feels necessary.

Contrast and colour

• Dark modules on a light background. That is what scanners expect. Inverted codes work in many apps and fail in some, so avoid them where reliability matters.
• Keep the dark colour genuinely dark. A mid-tone brand colour on white is often too little contrast once printed.
• Avoid red on the dark side. Some older laser scanners read with red light and see red modules as background.

Material and placement

• Matte beats gloss. A glossy finish throws back the phone flash and blanks part of the code.
• Flat beats curved. On a bottle or a cup, keep the code narrow enough that the curve does not distort it.
• Reachable. A code at ceiling height or behind a counter cannot be scanned however well it is made.

Order a proof

For anything with a real print run, get a physical proof and scan it with an ordinary phone, in the light the code will actually live in. A code that works on your monitor tells you almost nothing about how it will behave as ink.

More guides

• Error correction levels, and which one you actually need
• How big a logo can you put on a QR code
• What is really inside a WiFi QR code