QR codes on print: size and pitfalls
Once a QR code is printed, you cannot fix it. A code that scans fine on screen can turn out too small on paper or fail under store lighting more often than you might expect. Here is what to check before you print, in order.
1. Size depends on scanning distance
A common rule of thumb is scanning distance divided by 10 equals the width of the code. A business card or flyer held about 30cm (1ft) away needs at least 2 to 3cm (about 1in). A wall poster read from 2m (6.5ft) needs around 20cm (8in).
| Print item | Scanning distance | Recommended size |
|---|---|---|
| Business cards, stickers | 20-30cm (8-12in) | 2-2.5cm (0.8-1in) or more |
| Flyers, menus, table cards | 30-50cm (12-20in) | 3-5cm (1.2-2in) |
| Posters (A3, A2, tabloid) | 1-2m (3-6.5ft) | 10-20cm (4-8in) |
| Banners, window decals | 3m (10ft) or more | 30cm (12in) or more |
The more content you encode, the denser the modules get, which makes the same size harder to read. Shorten long URLs and include only what you need.
2. Always leave a quiet zone
A QR code needs empty space around it. The standard is four modules wide. If you push the code right up against background art or text for design reasons, the camera cannot find its edges. Set the margin in this tool to 2 or more, and keep that area clear on the printed piece too.
3. Dark code, light background
- The modules should be dark and the background light. Black on white is the safest. If you use a brand color, choose one that is dark enough.
- Many camera apps cannot read inverted codes (light modules on a dark background).
- Gold or silver foil and glossy coatings reflect light and hurt scanning. Keep at least the QR area matte.
4. Keep the center logo small
QR codes carry extra data so they can still be read when part of them is covered or dirty. This is called the error correction level, and the highest level, H, can recover about 30%. When adding a logo, set it to H and keep the logo under 20% of the code area. Never cover the three large squares in the corners, because they tell the camera where the code is.
5. File format and test before printing
Give your printer a file that stays sharp when enlarged, such as SVG. If you must use PNG, save it large enough to reach 300dpi at the printed size. For a 5cm (2in) code, that is about 600px or more.
Then print one copy at actual size and scan it with both the built-in iPhone camera and a built-in Android camera. Check that it reads from a bit farther away, at an angle and in dim light, and you will avoid almost every failure. Finally, confirm the code opens the right address and that the page looks good on a phone.
A static QR code cannot be changed later. If the content changes with each event, encode a fixed address on your own site and update only that page. It lasts much longer.