Print a QR code that people can actually scan

Keep empty space around the modules

A QR code needs a clear quiet zone around all four sides. Standard QR symbols use at least four modules of margin. Do not crop it away or place a caption inside it. Use dark modules on a plain light background, and avoid relying on subtle color differences. A layout that looks attractive on a large monitor can fail when reduced to a small label.

Calculate dimensions from the complete symbol

For an illustrative 29-module symbol, four modules on each side make the full width 37 modules. At 0.5 mm per module, the total width is 18.5 mm. This is a sizing example, not a guarantee of scanning at every distance. Longer payloads or a different error-correction setting can require more modules. Use the actual generated symbol and avoid stretching it into a rectangle.

29 + 4 + 4 = 37 modules
37 × 0.5 mm = 18.5 mm total width

Test the real distribution format

Export the intended file format, place it in the final design and print one proof at actual size. Scan with more than one phone under realistic light and distance. Check the decoded destination, not merely whether a scanner detects the symbol. If scans fail, simplify the payload, enlarge the symbol or improve contrast. Higher error correction does not remove the need for clear modules and margin.