A QR code that is not working can cost you leads and harm your brand reputation. Before you panic, know that the vast majority of problems stem from a handful of recurring causes that are straightforward to fix. This guide walks through the ten most common issues and their step-by-step solutions.
Design-related problems
Insufficient contrast between the dark modules and the light background is the number-one cause of scan failures. Maintain a minimum contrast ratio of 4:1, ideally 7:1 for optimal readability. Never invert the colours (dark background with light modules) because many readers cannot handle that configuration. Also avoid colour gradients on the modules, as they reduce detection by optical recognition algorithms.
Size and resolution issues
A QR code that is too small becomes unreadable, especially when printed on a physical medium. The basic rule is simple: the minimum size equals the scanning distance divided by ten. So for a code scanned at one metre away, plan for at least 10 cm per side. Also ensure the print resolution is at least 300 DPI to avoid blurry module edges that prevent reading.
Broken or incorrect destination URL
Verify that the URL encoded in the QR code is still live. Multiple redirects, expired SSL certificates or deleted pages are frequent causes of failure. Always test the QR code on at least three different devices before committing to print. If you use a URL shortener, make sure the service is reliable and that the short link has not expired.
Environmental scanning problems
Lighting plays a critical role. A QR code displayed behind glass can create reflections that block reading. Similarly, a code printed on a glossy or metallic surface will be difficult to scan in direct sunlight. Favour matte surfaces and position your codes away from direct reflections to guarantee a smooth scanning experience in all conditions.
Quiet zone and padding
Every QR code requires a white border called the quiet zone. This border must be at least four modules wide. Without this space the reader cannot detect the code boundaries and will fail consistently. If you embed a QR code in a busy design, increase the margin to compensate for the surrounding visual complexity.