QR code size and resolution: how big should you print it?
Size a printed QR code by the rule minimum width ≈ scan distance ÷ 10: a code scanned from 50 cm should be at least 5 cm wide, and one read across a 10 m room needs to be about 1 m. Resolution-wise, keep each module (the smallest square) above roughly 0.4 mm and leave a quiet zone of 4 empty modules around the code. For print, always export vector SVG rather than a small PNG — a low-resolution PNG enlarged onto a poster blurs the modules and is the classic reason a code scans on screen but not on the wall. Test the final size with a scannability check before printing a big run.
The one sizing rule: distance ÷ 10
The reliable rule of thumb is minimum code width ≈ scan distance ÷ 10. If people will scan from arm's length (about 30–50 cm), 3–5 cm is enough. A code on a poster read from 3 m needs to be around 30 cm; one across a 10 m room needs roughly 1 m. Going bigger never hurts scannability — only going too small does. When in doubt, print it larger than you think you need.
Resolution: it's really about module size
A QR code is a grid of small squares called modules. What matters for printing isn't DPI in the abstract — it's how big each module ends up. Keep modules at roughly 0.4 mm or larger and a camera can resolve them comfortably. Two things shrink your modules without you noticing:
- Too much data. A long URL or a full vCard forces a higher-version code with more, smaller modules. Shorten the content (or print larger) to keep modules coarse.
- Printing small. The same code at 2 cm has half the module size it has at 4 cm. Combine 'lots of data' with 'printed small' and the modules smear together.
- Low-res source image. A 200 px PNG stretched onto a banner turns crisp squares to mush regardless of the printer.
Why SVG beats a big PNG for print
For anything printed, export vector SVG. An SVG describes the modules as shapes, so it prints razor-sharp at any size — business card or billboard. A raster PNG has a fixed pixel grid; enlarge it past its native size and the edges blur. If you must use PNG, generate it at the final print dimensions at 300 DPI rather than scaling a small one up. QR Cat exports SVG free on every generator, so reach for it whenever the code leaves the screen.
Don't forget the quiet zone
Size includes the quiet zone — the empty margin around the code, ideally 4 modules wide. Designers often crop it tight to fit a layout, and then scanners can't tell where the code begins. The quiet zone is part of the code's footprint: budget for it when you decide how much space the code needs on the page.
Test at final size before the print run
The cheapest insurance against a dead print run is to test the code at its real output size first. Run it through QR Cat's scannability test, which decodes it scaled down and at low contrast to mimic distance and small print. If it only survives at full size, it's too fragile for a small label — size up or simplify the content before you commit to a thousand copies.
Frequently asked questions
What's the minimum size for a printed QR code?
Use scan distance ÷ 10. For arm's-length scanning (30–50 cm), about 3–5 cm wide is enough. Below ~2 cm, codes with a lot of data start to fail. Always include a quiet-zone margin around it and test at the final size before a big print run.
What DPI or resolution should a QR code be?
Aim to keep each module (smallest square) above ~0.4 mm in the final print; at 300 DPI that's comfortably resolved. More important than a DPI number: export vector SVG so the code is resolution-independent, or generate the PNG at the actual print dimensions rather than scaling a small image up.
Why does my QR code look blurry when printed large?
You almost certainly enlarged a low-resolution PNG. Raster images have a fixed pixel grid that blurs when stretched. Re-export the code as SVG (vector, sharp at any size) or regenerate the PNG at the final print size and DPI.
How big should a QR code on a poster or billboard be?
Apply distance ÷ 10 to the expected scan distance. A poster read from 3 m wants roughly a 30 cm code; a billboard scanned from 10 m needs about 1 m. Keep the content short so the modules stay large, and leave a generous quiet zone.