What is the minimum size for a QR code to scan?

The minimum size is 2cm × 2cm (0.8 inches) for close scanning at arm's length. For posters and signs, the QR width should be 1/10 of the expected scanning distance.

Why won't my colored QR code scan?

Colored QR codes need sufficient contrast between the foreground and background. Dark colors on light backgrounds work best. Black on white is foolproof. Avoid low-contrast combinations like yellow on white or dark blue on black.

Can damaged QR codes still work?

QR codes have built-in error correction that can recover from some damage. However, if critical areas (like the three corner squares) are damaged, the code may not scan. Scratches, folds, or partial coverage can break the code.

Do I need a special app to scan QR codes?

Most modern smartphones can scan QR codes using the built-in camera app. iPhone (iOS 11+) and most Android devices support native QR scanning without any additional apps.

Why Won't My QR Code Scan?

Most scanning problems have simple causes. Run through this checklist to find yours.

The Usual Suspects

Size: Is the code big enough? Minimum 2cm × 2cm for close scanning, larger for distance. Rule of thumb: QR width should be 1/10 of expected scanning distance.

Contrast: Are the colors different enough? Dark on light works best. Black on white is foolproof. See our colors guide.

Damage: Is anything obscuring the code? Scratches, folds, stickers, or partial coverage can break it.

Focus: Can the camera actually see it clearly? Clean lens, steady hand, good lighting.

When in doubt, go bigger and simpler. Larger codes with high contrast always scan better.

Size Problems

Minimum sizes:

2cm × 2cm (0.8") – Absolute minimum for arm's-length scanning
3cm × 3cm (1.2") – Recommended minimum
For posters and signs, scale up based on viewing distance

If it's too small, print it larger. No other fix.

Contrast Problems

QR scanners work by detecting contrast between dark and light areas. When colors are too similar, the scanner can't distinguish the pattern.

Won't scan reliably:

Light gray on white
Dark blue on black
Pink on red

Fix: Use dark foreground on light background. If your brand colors don't have enough contrast, use black on white for the QR code itself.

Physical Damage

QR codes have error correction—they can handle some damage. But too much breaks them. Reprinting is usually the only fix for:

Deep scratches through the pattern
Fading from sun or wear
Fold lines running through the code

Camera Issues

If the code is fine but still won't scan:

Can't focus: Clean the lens, hold steadier, tap to focus, move closer or farther No built-in scanner: Try Google Lens (Android) or a dedicated QR app Old phone: Some very old devices struggle—try a different phone

Environmental Issues

Poor lighting: Add light or use phone flashlight Glare: Change angle, use matte materials instead of glossy Curved surface: Scan straight-on, try different angles

Static Code Too Dense

If you're using a static code with a long URL or lots of data, the pattern becomes very dense and harder to scan at small sizes.

Fix: Switch to a dynamic code (uses a short redirect URL) or print larger. See dynamic vs static codes for more on the difference.

Common Questions

Why does it work on my phone but not others? Test on both iPhone and Android. Different apps have varying QR support.

Why does the customized version fail when plain black-on-white works? Customization can reduce scannability. Simplify: reduce logo size, increase contrast.

It worked yesterday but not today? For dynamic codes, check your dashboard—maybe the destination changed. For static codes, check for physical damage.

Do QR codes expire? Static codes never expire. Dynamic codes work as long as your account is active.