QR Code Best Practices: Do This, Not That

A QR code fails for boring, avoidable reasons: it is too small, too low in contrast, crammed against other elements, or points to a page that does not work on a phone. Getting the basics right makes almost any code scan reliably. This guide covers the practices that matter most and the mistakes to avoid.

What Size Should a QR Code Be?

A QR code should be at least 2 by 2 centimetres, or about 0.8 inches, for scanning at close range. The further away people scan, the larger it must be. A rough rule is a 10 to 1 distance-to-size ratio, so a code scanned from 2 metres should be around 20 centimetres wide.

When in doubt, make it bigger. A slightly oversized code always scans, while an undersized one frustrates people and gets ignored.

How Do Contrast and Quiet Zone Affect Scanning?

Scanners rely on contrast between the dark modules and the light background. Dark on light works best, ideally near black on white. Avoid light codes on dark backgrounds, low-contrast colour pairs, or busy photo backgrounds, since these often fail to scan.

Every code also needs a quiet zone, a clear margin of empty space around it, so the scanner can find its edges (ISO). Crowding the code with text or graphics right up to its border is a common reason codes will not read.

Should You Test QR Codes Before Printing?

Always test before you print or publish. Scan the final code with more than one phone, on both iPhone and Android if you can, and confirm it opens the correct page. Test the printed version too, not just the screen, since paper and print quality can change the result.

Testing takes a minute and prevents the expensive mistake of printing thousands of materials with a code that does not work.

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Error Correction and Logos

QR codes include error correction that lets them scan even when part of the pattern is damaged or covered. The highest level, H, allows up to about 30% of the code to be obscured (Denso Wave). If you place a logo in the centre, use a high error correction level so the code still reads reliably.

Keep any logo small and centred, and always test the finished code, since too large a logo can push even a high error correction code past its limit.

The Most Common QR Code Mistakes

The mistakes that break QR codes are predictable: making them too small, using low contrast, removing the quiet zone, adding an oversized logo, never testing, and pointing the code at a slow or desktop-only page. Another is using a dynamic code on a subscription that lapses, which silently kills every printed code.

Fix these and your codes will scan the first time, every time. Do the basics well and the technology simply works.

Frequently Asked Questions

What is the minimum size for a QR code?

A QR code should be at least 2 by 2 centimetres, or about 0.8 inches, for close-range scanning. For greater distances, scale it up using a rough 10 to 1 distance-to-size ratio. When unsure, make it larger, since an oversized code always scans and an undersized one often fails.

Why is my QR code not scanning?

The usual causes are small size, low contrast, no quiet zone around the code, an oversized logo, or a damaged printout. Check that the code is dark on a light background with a clear margin, then test it on more than one phone to confirm it opens the right page.

Do QR codes need a border or quiet zone?

Yes. A quiet zone is the clear margin of empty space around the code that lets a scanner find its edges. Crowding text or graphics right up to the code is a common reason it will not scan. Leave a clean border on all four sides.

Can I put a logo in a QR code?

Yes, if you use a high error correction level, which lets up to about 30% of the pattern be covered and still scan. Keep the logo small and centred, and always test the finished code, since an oversized logo can push even a high correction code past its limit.

Should I test a QR code before printing?

Always. Scan the final code on more than one phone, ideally both iPhone and Android, and check that it opens the correct page. Test the printed version as well as the screen, since a minute of testing prevents printing thousands of materials with a code that does not work.

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