QR codes on a flyer: size, placement and testing

A QR code is the only thing on a flyer that asks the reader to take out a phone. That is a big ask, and most codes on noticeboards fail it for ordinary reasons: printed too small for the amount of data in them, crowded by a border, placed with no hint of what they do, or pointing at a page that no longer exists. None of those are design problems. They are checks, and they take ten minutes.

Size: modules, not millimetres

A QR code is a grid of small squares called modules. Denso Wave, the company that developed QR Code, explains that versions run from Version 1, which is 21 by 21 modules, to Version 40, which is 177 by 177, with each version adding four modules per side. The more data you encode, the higher the version and the more modules the code needs.

That is why the same printed width can scan easily or not at all. What a phone camera has to resolve is the individual module, so the useful question is how big each module ends up once the code is printed. A 25 millimetre code with 29 modules across, including the margin, gives modules of about 0.86 millimetres. The same 25 millimetres holding a Version 10 code gives modules of about 0.38 millimetres, less than half the size, from the same patch of paper.

The table below works that out for common versions at two printed widths, using the module counts Denso Wave publishes. The practical rule that follows is simple: shorten what you encode before you enlarge the code. A short, clean link produces a low version code whose modules stay large, while a long tracking URL full of parameters can push the version up and shrink every module.

Denso Wave’s own printing example shows the arithmetic in the other direction. A Version 3 code of 29 modules printed at 0.254 millimetres per module comes to 7.366 millimetres, and adding the margin brings it to 9.398 millimetres square. That is a code for a product label read at a hand’s distance, not for a flyer on a wall.

The quiet zone

Denso Wave states that a QR Code requires a margin four modules wide on all sides. This quiet zone is how a phone finds where the code starts, and it is the part designers most often steal. A thin frame, a photograph that runs up to the edge or a coloured panel edge inside that margin can stop a scan entirely.

Treat the margin as part of the code’s footprint. When you decide a code will be 30 millimetres wide, the modules and the margin share those 30 millimetres.

Colour affects detection too. Dark modules on a light ground give a camera the strongest edge to find, and a code in two similar mid tones, such as grey on a pastel panel, gives it very little. If the design sets the code in brand colours or reverses it to light on dark, that is not automatically a failure, but it is exactly the kind of choice that has to survive a printed test rather than a glance at the screen.

Placement: next to the action, with a label

Put the code beside the thing it lets someone do. The open day flyer example is a good model. Its three step visit design breaks the day into register, pick a tour and ask about fees, and puts the QR slot beside the register link, so the code and the first step read as one instruction.

The bookshop event flyer example does the same for tickets. Of Marram Books’ three designs, only the ticketing sheet carries a code, and it goes to the booking page, next to the run of the evening and the venue details. The window poster, which is a passage of the novel and almost nothing else, has no code at all, because nobody books from across a street.

Always add a label. “Scan to register” or “Scan for tickets” tells a reader what the phone is for before they reach for it, and a code with no label is easy to ignore. Keep a short typed web address near the code too, for readers whose camera will not cooperate.

What the code should link to

The destination matters more than the code. Link to one page that finishes the job the flyer started: a booking form, a registration page, a menu. Avoid linking to a home page and hoping the reader finds the rest.

Make the page work on a phone, since that is the only device that will ever arrive there. Make it permanent for the life of the flyer. A code printed on five hundred sheets that points at a page removed next month becomes five hundred broken promises.

On research posters, the code does a different job: it hands over what the board had no room for. The survey research poster example puts its code in the title band and links the questionnaire and the data tables, and the clinical trial poster example sets its code at the right of the title band opposite the institution mark.

Error correction and testing

QR codes carry error correction so a smudged or damaged code can still be read. Denso Wave describes four levels and says level M, restoring about 15 percent, is the one most often selected, with Q or H suited to dirty environments and L to clean ones with a lot of data. Higher levels mean more modules, so there is a trade between robustness and density.

Then test, because nothing else settles it. Print one sheet at the final size. Pin it where the flyer will actually go, in the same light. Scan it from the distance a person would stand, with at least two phones of different ages. Check that the link opens the right page and that the page loads quickly on mobile data. If any scan hesitates, shorten the link or enlarge the code and print another test.

Common mistakes

A long URL in a small code. Every extra character can add modules and shrink them.

No quiet zone. A border or photograph inside the four module margin breaks detection.

No label. A code without a reason to scan it gets ignored.

A destination that expires. Temporary campaign pages and lapsed redirect services turn printed codes into dead ends.

Testing on screen only. A code that scans from a monitor may fail on paper under fluorescent light. Resolution matters too: what DPI a flyer needs explains why an A4 flyer does not need more than it gets. For everything else that belongs beside the code, see what to put on a flyer.

Build it

In the flyer builder a QR code can only appear on a design that ships with a QR slot. There is no QR item in the Add items panel, so a code cannot be added to a design without one. On a design that has a slot, you type the link or text to encode, or upload a QR image made elsewhere. The QR code flyer page explains the slot, and the template, theme and size tutorial covers picking a design, including one with a QR code, before you generate. Export size helps the code stay crisp: an A4 page captures at 2480 by 3508 pixels, which is A4 at 300 DPI.