QR code too small to scan: the minimum size
A QR code that is too small is the most common reason a printed one will not scan. The camera needs to see each small square, and ink spread or a rough surface makes small squares blur together.
Here is how big is big enough.
What is the smallest QR code that will scan?
As a rule, 2 cm (0.8 inch) square is the practical minimum for a short web address, read from a hand-held distance. Smaller works only on smooth, high-quality print.
- Business card: about 2 to 2.5 cm.
- Flyer or menu: 2.5 to 3 cm.
- Poster read at 1 meter: about 10 cm.
How does distance change the size?
A reasonable rule is to make the code about one tenth of the scanning distance. A code scanned from 1 meter should be about 10 cm square.
Does a long web address make it worse?
Yes. A longer address means more squares, so each square is smaller at the same size. A dynamic code with a short address makes a simpler pattern that scans from farther away.
How do I fix a code that is too small?
Print it larger, simplify the address, and keep the white border. If the space is fixed, use a dynamic code with a short address.
Questions
Does the border count in the size?
Measure the code itself. Keep the white border on top of that.
Can a code be too big?
It can be too big to fit in the camera view at close range, but that is rare.
Do colors change the minimum size?
Low contrast makes a code harder to read, so dark on light is best.
What about a code on a screen?
Make it large enough that the squares are clearly visible, and test it.
Where is the full guide?
See how big a QR code should be.
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