How to Test a QR Code Before You Print It

6 min read  ·  QR Code Guides

Most QR code failures happen for one of three reasons: the code was never tested before printing, it was only tested on the screen version, or it was tested in conditions that did not match where it would be displayed. A ten-minute test before you commit to any print run prevents all three. Here is a systematic approach.

Step 1: Verify the content first

Before scanning anything, confirm the information encoded in the code is correct. This sounds obvious, but a typo in a URL, a missing digit in a phone number or an incorrect WiFi password is the single most common cause of QR code failure — and it has nothing to do with the code itself.

If your code links to a URL, copy the URL out of the generator and paste it into a browser tab. Confirm the page loads, that it is the right page, and that it loads on a mobile browser without any login prompts or errors. If it is a vCard, review every field. If it is a WiFi code, manually try the network name and password in your phone's WiFi settings before generating the code.

Step 2: Scan the on-screen preview

The QR code preview in DoMyQR.com is a live, accurate version of the code you will download. Scanning the preview confirms the code itself is generating correctly.

Use your phone's native camera app rather than a third-party QR reader for this test. The native camera is what most of your users will use, and it is the most representative test. Point it at the screen, wait for the code to be recognised and confirm the action it triggers is correct — the right URL opens, the correct contact prompt appears, WiFi connects to the right network.

Step 3: Test on a second device

QR code scanning is handled by the camera software on each phone, and different manufacturers implement this differently. A code that scans instantly on an iPhone may take two or three seconds on an Android phone, or may require the camera to be held at a specific distance. This is usually fine, but it is worth knowing before it surprises a customer.

If you only have one phone available, ask a friend or colleague to scan the code on their device. The key thing to verify is that the code is readable at all, not just on your specific camera.

Step 4: Print a test copy at the intended size

This is the step most people skip, and the one that catches the most problems. A QR code that looks crisp and clear on a monitor can lose critical detail at small print sizes. Individual modules become indistinct if the code is dense and the print size is small.

Print a single copy at the exact size it will appear in the final design — not larger. If the code is going on a business card at 20 mm × 20 mm, print it at 20 mm × 20 mm. If it is on a table card at 35 mm, print that size. Scan the physical print.

Most desktop printers print at 300 dpi, which is adequate for sizes above 25 mm. For smaller sizes, ask your print shop to produce a proof at their print resolution before committing to a run.

Step 5: Test in the actual environment

Scan the physical print in the conditions where customers will encounter it. This is particularly important for:

• Restaurant table cards — test at table height, in the venue's actual lighting, which is often dimmer than your home or office
• Outdoor signage — test in daylight, since direct sunlight can create glare on laminated surfaces
• Retail shelf or packaging — test in the aisle or display environment, not in a back office
• Event posters — test from the scanning distance a passerby would naturally use (usually 30–60 cm)

If the code takes more than two or three seconds to scan, or requires the phone to be repositioned to find the code, consider increasing the print size or reducing the data complexity of the code.

Step 6: Test what happens after the scan

The QR code is only half the experience. After scanning, you need to verify that the destination works correctly on a mobile device. For URL codes, open the link on a phone browser and check:

• The page loads within two to three seconds on a mobile connection
• The content is readable without zooming
• No login or account creation is required to access the content
• The page does not immediately redirect elsewhere in a way that confuses users
• The correct content is shown — not a 404 error, a login wall or an outdated version

For WiFi codes, confirm the phone successfully connects to the network. For vCard codes, confirm the contact details are correct and the entry saves without errors. For email codes, confirm the correct email address and subject line appear in the compose window.

The pre-print checklist

• URL or content has been verified manually before generating the code
• On-screen preview scanned successfully with native camera app
• Tested on a second device
• Physical test print produced at the intended print size
• Test print scanned successfully in the actual display environment
• Destination (URL, contact, WiFi, etc.) works correctly on a mobile browser or native app
• Short fallback URL or contact information included near the code in case of scan failure

When to regenerate instead of fix

If a test reveals that the code is not scanning reliably, the fix depends on the cause. If the content is correct but scanning is inconsistent, increase the print size or switch to a lower error correction level (if you are not using a logo) to reduce density. If the code has a logo overlay and is failing, switch from Q to H error correction.

If the URL or content was wrong, regenerate the code from scratch with the correct information. Do not try to patch a printed code — the fix for a wrong URL is always regeneration, not a sticker over the top.

QR code performance varies by device, environment and print quality. This checklist covers common scenarios but is not exhaustive.