Choosing the right size for a QR code is essential to guarantee a first-time scan. Too small and it becomes unreadable; too large and it wastes valuable space on your medium. This guide provides the calculation formula and per-medium recommendations so you can size your code optimally every time.
The basic formula
The universal rule for calculating minimum QR code size is: divide the expected scanning distance by ten. If customers will scan at 30 cm (business card), the minimum size is 3 cm. For a poster read at 2 metres, plan for at least 20 cm. This formula applies under normal lighting with standard contrast. In challenging conditions, increase the size by 20 to 30 per cent to be safe.
Recommended sizes by medium
On a business card the ideal size is 2 to 3 cm per side. On an A5 flyer, plan for 3 to 4 cm. For an A4 restaurant menu, aim for 4 to 5 cm to facilitate reading even in dim lighting. On an A3 or A2 poster the QR code should measure at least 8 cm. For billboards and roll-up banners, the size can reach 30 cm or more depending on the expected reading distance and the speed at which viewers pass by.
Impact of content complexity
The more data a QR code contains, the more modules it has and the larger it must be to stay readable. A code containing a simple short URL will be far more compact than a vCard code with full contact details. If your content is dense, use a URL shortener to reduce the encoded data volume and thus decrease the number of modules needed. This lets you keep a reasonable size while preserving readability.
Resolution and file format
For print, always export your QR code in SVG vector format to guarantee perfect sharpness at any print size. If you must use a bitmap PNG format, ensure the resolution is at least 300 DPI at the final print size. A pixelated QR code loses scan reliability and makes your marketing material look unprofessional.