For QR Codes that will be scanned up close (e.g., on Products, in Magazines):
- 32 mm (1¼ inches), excluding the margin, is the minimum size that guarantees that all camera phones on the market will be able to properly read the QR Code.
- 26 mm (1 inch), excluding the margin, is the recommended size that works with roughly 90% of the phones on the market.
- 10 mm (.4 inch), excluding the margin, works well with the latest smartphones, which have improved macro capabilities.
For QR Codes that will be scanned from afar (e.g, on Signage):
- The simplest approach is use a QR Code size that is at least one tenth of the scanning distance, excluding the margin.
- For example, a code on a Billboard that will be scanned from a distance of 10 m (32 ft) should be at least 1 m (3.2 ft) in size, excluding the margin.
For all QR Codes:
- Use a minimum margin of 4 blocks.
- Good contrast between the background and the QR Code color is very important. The QR Code should have a dark color with a light background color.
- Some QR Code Readers can not read reversed colors (e.g., light color with a dark background color, white with black background color).