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How to test a QR code before you print it

Published 7 September 2026 · 3 min read

A print run is the one place a QR code mistake costs real money. Ten checks, twenty minutes, and it will not happen to you.

Not on your computer. On a phone, on mobile data, in a private window so nothing is cached. It should load in under three seconds and be readable without zooming.

Do this

A mobile page that loads in two seconds and fits the screen.

Not this

A 12 MB PDF that takes ten seconds on café Wi-Fi and needs pinch-zooming.

Scanners show the domain before opening. If it is a third-party shortener, that is what people will see. Use your own domain or a dynamic code on a service you trust to stay online.

3. Decode the artwork

Export the final artwork and drop it into the decoder. The text that comes out is what people will get. Check every character, especially in Wi-Fi passwords and phone numbers.

4. Run the scannability tester

The scannability tester decodes the artwork after shrinking, blurring, lowering contrast and inverting it, and measures the quiet zone. Fix anything it flags now; it is cheaper than after printing.

Do this

Six checks passed, quiet zone 4.5 modules.

Not this

Fails when shrunk to 240 px, which is what a scan from two metres looks like.

5. Check the size against the distance

Distance ÷ 10. A poster read from 2 m needs a 20 cm code. The size calculator also tells you the module size so you know whether the printer can hold it. Details in the size guide.

6. Check the quiet zone survives the layout

Four modules of blank space on every side, inside the trim, away from text, borders and folds. Designers crop it off more often than any other mistake.

Do this

Code placed with a clear margin equal to its own width from any edge or text.

Not this

Code nudged against a border rule to save space, so the scanner cannot find the finder patterns.

7. Print the test sheet on the final stock

The test sheet prints your code at eight sizes, four error-correction levels and three contrast pairs, plus a 100 mm bar. Use the actual paper: gloss, card, vinyl, whatever the run will be on.

8. Check the scale bar

If the bar is not 100 mm, the print dialog scaled the page. Fix it and reprint. Otherwise every size you tested is a lie.

9. Scan from the real distance with the worst phone

Stand where the reader will stand, in the light they will have, with the oldest phone you can borrow. Then try a new one. Both should work first time.

10. Hand it to a stranger

Give the printed proof to someone who has not seen the project. Say nothing. If they hesitate, the call to action or the placement needs work, not the code.

In practice

Keep the proof. When the run arrives, scan one copy from the box before distributing any. Printers occasionally re-rasterise artwork.

Try it in QR Studio

QR Studio runs the artwork checks automatically on every export and warns before a failing design leaves the app.

Checklist

  • Link opens fast on a phone, on mobile data, in a private window
  • HTTPS on a domain you control or trust
  • Artwork decoded and every character checked
  • Scannability tester passed
  • Size at least distance ÷ 10, module size above 0.5 mm
  • Quiet zone intact in the layout
  • Test sheet printed on the final stock
  • 100 mm bar measures 100 mm
  • Scanned from the real distance on an old phone and a new one
  • A stranger scanned the proof unprompted

Try it yourself

Upload the export and get the six-check verdict in a second. Then print the test sheet.

Test your artwork now

Frequently asked questions

I scanned it on my phone and it worked. Is that enough?

No. Your phone, your screen and your lighting are the best case. Test printed, on the final stock, on an older phone, in the real place.

How many phones should I test with?

At least two: a recent iPhone and an Android phone a few years old. Add a dedicated scanner if that is what will be used.

What if the printer's proof is slightly offset or scaled?

Check the 100 mm bar on the test sheet. If it is not 100 mm the whole run will be wrong; fix the print settings before approving.

Related reading

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