QR code size guide: how big to print for any scan distance

Minimum QR code size by scan distance

The rule of thumb used by printers and signage designers is that the width of a QR code should be at least one tenth of the distance from which people will scan it. Divide the distance by ten and you have the minimum width.

Scan distance	Minimum width
0.5 m (arm’s length: table cards, business cards)	5 cm
1 m (counter displays, shelf labels)	10 cm
2 m (posters at eye level, shop windows)	20 cm
5 m (banners, trade-show walls)	50 cm
10 m (billboards, building signage)	1 m

This is a minimum for a simple code with good contrast in decent light. Use the calculator above to adjust it for your content, then read on for the reasons the answer moves.

Why module count matters

A QR code is a grid of small squares called modules. A short URL fits in a 25 × 25 grid (version 2); a full contact card or a long tracking URL might need 57 × 57 (version 10) or more. At the same printed width, the second code’s modules are less than half the size of the first, and the phone has to resolve each one.

The practical limit is the module, not the code. For print, each module should be at least 0.5 mm wide, and 1 mm or more is comfortable. A 25-module code at 0.5 mm per module is 12.5 mm wide plus its quiet zone; a 57-module code needs 28.5 mm at the same module size. The capacity line under the preview on every generator page shows the module count, so you can check before exporting. If the count is high, shorten the content: a short path on your own domain instead of a long URL, or the MeCard option instead of a full vCard.

DPI and pixel size for print

Printers work in dots per inch, and 300 dpi is the standard for anything viewed up close. To find the pixel size you need, multiply the printed width in inches by 300: a 5 cm (2 in) code needs 600 px, a 20 cm (8 in) poster code needs 2,400 px. Going the other way, pixels ÷ dpi gives the printed width, so a 1,024 px PNG prints cleanly at up to 8.7 cm.

For anything larger than a flyer, skip the arithmetic and export SVG or PDF. Both are vector: the modules are drawn as shapes rather than pixels and scale to any size without softening. Print shops prefer them, and the PDF export lets you set the physical size in millimetres directly.

Quiet zone

The quiet zone is the blank border around the code, and the standard asks for four modules on every side. It is part of the code’s size, not decoration: scanners use it to find the edges. A 25-module code with its quiet zone is 33 modules wide, so at 1 mm per module it needs 33 mm, not 25 mm. Keep the zone the same colour as the code’s background and keep text, borders and photographs out of it. The generator includes it by default and warns if you reduce it below two modules.

Error correction and logos

Error correction lets a scanner rebuild damaged parts of the code. Level L recovers about 7 percent of the area, M 15 percent, Q 25 percent and H 30 percent. Higher levels are more robust but add modules: an H code holds roughly 40 percent more modules than an L code for the same content, so it needs to be printed larger to keep the module size the same.

A logo covers modules, so it consumes some of that recovery budget. The generator switches to H automatically when you upload a logo and caps the logo at 30 percent of the width. Even so, a logo on a small code is the most common cause of a code that verifies on screen and fails on a business card. If the code will be printed under 3 cm, consider leaving the logo off.

Material and lighting

Matte paper and vinyl scan best. Glossy laminates, metallic inks, clear acrylic and glass all produce reflections that wash out modules under overhead lights. Very dark or textured backgrounds reduce the contrast the scanner relies on. For outdoor codes, allow for fading: print larger than the minimum and use a laminate or UV-resistant ink. Codes in dim environments, such as restaurants in the evening, benefit from being one size up, because phone cameras struggle to focus on small detail in low light.

Screens vs paper

On a phone or laptop screen, a code needs to be large enough that the scanning phone can hold it in focus at a comfortable distance, roughly 2.5 cm on screen for a scan from 20 cm. Screen brightness, reflections and cracked glass all matter. On a TV or projector across a room, apply the distance rule as you would for a poster: a code scanned from 4 m needs to be around 40 cm on the display. Avoid animated backgrounds behind the code and give it a solid white panel.

Test before you print

Print one copy at the intended size on the intended material. Mount it where it will live. Then scan it from the real distance with two phones, one iPhone and one Android, using their built-in camera apps rather than a dedicated scanner app. If either hesitates, go up a size or reduce the module count. The verification badge in the generator confirms the file decodes correctly; only a physical test confirms the print does. The QR code reader is useful for the last step: photograph the print and upload it to see whether the content decodes cleanly.