QR code sizes and print resolution
A code that's perfect on screen can fail on a poster. Physical size, scan distance, resolution, and margin all decide whether a printed code reads. Here are the rules of thumb that keep codes scannable from a business card to a billboard.
The 10:1 scan-distance rule
The most useful guideline: a QR code's width should be at least one-tenth of the distance it will be scanned from. Scanners need the code to occupy enough of the camera frame to resolve individual modules.
| Scan distance | Minimum code width (≈10:1) |
|---|---|
| 30 cm (handheld, a card) | ~3 cm |
| 1 m (a flyer or table sign) | ~10 cm |
| 3 m (a wall poster) | ~30 cm |
| 10 m (a billboard) | ~1 m |
Treat these as minimums and add margin in practice — real conditions (motion, poor light, cheap cameras) want a bit more.
Minimum sizes
Regardless of distance, avoid printing a standard code much smaller than about 2 cm (roughly 0.8 in) square. Below that, modules get too fine for many cameras and printers to resolve cleanly. Denser codes — long URLs, contact cards, high error correction — need to be printed larger because they pack more, smaller modules into the same area. Keep payloads short to allow smaller print; see design best practices.
Resolution and DPI
For print, design at 300 DPI (dots per inch) at the final physical size — the standard for crisp printing. At 300 DPI, a 3 cm code is about 350 pixels wide; a 10 cm code about 1,180 pixels. When exporting a raster PNG, choose a pixel size that meets or exceeds that target. This generator exports PNG up to 4,096 px, comfortably enough for large print.
Enlarging a low-resolution PNG produces blurry, soft-edged modules that scanners struggle with. Export at the size you need from the start, or use a vector.
The quiet zone
Every code needs a clear margin — the quiet zone, ideally 4 modules wide on all sides — so a scanner can isolate it from surrounding content. Don't crop tight to the pattern, and don't place text or graphics inside the margin. Shrinking the quiet zone is one of the most common reasons a well-printed code still fails. The generator's margin control sets this for you.
Sizing for screens and placement
Not every code is printed. When one appears on a slide, a TV, or a web page, different rules apply:
- Screens have their own "distance." A code in a slide deck is read from across a room — make it large on the slide, just as you would a poster.
- On-screen codes can be scanned directly, but glare and viewing angle still matter; keep contrast high and the code static (not animated past).
- Leave bleed and breathing room in print. Don't place a code right at a trimmed edge or across a fold — both can clip the pattern or its quiet zone.
- Avoid curved or flexible surfaces where you can. Bottles, sleeves, and creased paper distort modules; if unavoidable, print larger and raise error correction.
Vector vs raster for large formats
For anything that will be resized or printed large — signage, posters, packaging — export SVG. As a vector, it scales to any dimension with perfectly sharp edges and no resolution ceiling. Use PNG for fixed-size digital uses like a web image or a slide. The full comparison is in PNG vs SVG.
Export at the right size
Generate a code, set the quiet-zone margin, and export sharp PNG up to 4,096 px or infinitely scalable SVG.
Open the generatorFrequently asked questions
How big should a QR code be?
At least one-tenth of the scan distance (the 10:1 rule). About 3 cm for a handheld card, 10 cm for a 1 m sign, and 30 cm for a poster read from 3 m. Keep ~2 cm as an absolute minimum.
What DPI should I use for printing?
300 DPI at the final physical size is the standard for crisp print. Export a PNG with enough pixels to meet that, or use a vector SVG.
What is the quiet zone and how wide should it be?
The clear margin around the code, ideally 4 modules wide on all sides. It lets scanners separate the code from its surroundings; cropping it is a common cause of scan failures.
Why does my small QR code fail to scan?
Likely the modules are too fine for the camera or printer, the payload is too dense, or the quiet zone was cropped. Print larger, shorten the data, and keep the margin.