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QR code not scanning: how to fix it

If customers point their camera at your code and nothing happens, the problem is almost always the printed image rather than your Trustaroo account. Work through the checks below in order; most cases are solved by reprinting at the right size from the original download.

Rule out the link first

If the camera does open a page and that page says the link was not found, this is not a scanning problem. See Link not found instead.

A code that is too small has bars finer than the camera can resolve. Print at least 2 by 2 centimeters for something held in the hand, such as a receipt or a card. A table talker wants 3 to 4 centimeters, and a poster read from a meter or more away wants 6 centimeters or more.

The rule of thumb is that the code should be about a tenth of the distance it is read from. A code on a wall behind the till is read from two meters, so it needs to be roughly 20 centimeters across.

Contrast and quiet space​

Cameras look for dark modules on a light field. Codes lose reliability when they are printed light grey on white, reversed to white on a dark background, printed over a photo or a pattern, or tinted in a brand color with too little contrast.

Leave an empty margin of at least four module widths, roughly the width of two of the small squares, on all four sides. Text or a border pressed against the code stops phones from finding its edges.

Glare, damage and lamination​

  • Glossy lamination under a spotlight reflects straight back into the lens. Use a matte finish, or angle the card away from the light.
  • Codes on tables collect grease, scratches and coffee rings. Replace them on a schedule rather than waiting for complaints.
  • A code folded across a crease, or printed over the fold of a menu, no longer scans flat.

Image quality​

Use the file you downloaded from Trustaroo. Two habits break codes:

  • Screenshots. A screenshot of the code on your monitor is far lower resolution than the download, and enlarging it produces soft, blurred edges.
  • Scaling up in a document. Dragging a small PNG larger in a text editor or slide deck does not add detail. Insert the original file at the size you want, or use the printable PDF, which is already laid out for A4, Letter and A5.
Print the PDF when in doubt

The printable PDF contains the code at a tested size along with short instructions for customers. It removes every scaling and layout decision from the process.

Camera distance and behavior​

Phones focus at roughly 20 to 30 centimeters. Held closer, the code fills the frame and the camera cannot focus; held further away from a small code, there is not enough detail. Ask the customer to hold still for two seconds.

A handful of older phones need a separate scanning app rather than the camera. If one customer cannot scan and everyone else can, that is the likely reason, and your short link works as a fallback.

Test before you commit​

  1. Print one copy of the new material.
  2. Scan it with an iPhone and an Android phone, in the light the code will actually live in.
  3. Scan it again from the distance a customer will use, not from arm's length above your desk.
  4. Only then print the rest of the run.