The more data you encode, the more modules the QR code needs, and the denser and more difficult to scan it becomes. Where possible, use a short URL. If your destination URL is very long, consider using a URL shortener first. A shorter URL produces a smaller, cleaner code that scans faster and more reliably.
Never send a QR code to print without testing it first. Scan the generated code with at least two different devices — ideally an iPhone and an Android phone — before committing to a print run. Check that the destination is correct and loads properly.
QR codes work best with high contrast between the dark modules and the light background. Black on white is the most reliable combination. If you are using custom colours, ensure the foreground is significantly darker than the background. Light-coloured QR codes on light backgrounds, or dark codes on dark backgrounds, often fail to scan.
Avoid using very similar shades of colour for the foreground and background. If in doubt, download the SVG and test it on a printed proof before finalising.
For reliable scanning, print QR codes at a minimum of 2 cm × 2 cm. For codes with more data (longer URLs, vCards), aim for at least 3 cm × 2 cm. Very small printed codes are difficult for smartphone cameras to focus on, especially in poor lighting.
For large format print (posters, banners, signage), download the SVG version so the code scales without quality loss.
If you are placing a logo over the centre of the QR code, always use error correction level H. The logo covers data modules, and high error correction ensures the scanner can recover the complete content from the remaining modules.
Every QR code needs a margin of empty space around it — called the quiet zone — to help scanners detect the boundary of the code. This should be at least 4 modules wide on all sides. When placing a QR code in a design, do not let other graphic elements touch or overlap the code.
For screen use, PNG is fine. For anything that will be printed, always download the SVG. SVG is a vector format that scales to any size without becoming pixelated. A 300 px PNG printed at 10 cm will look blurry; an SVG at 10 cm looks perfect.
If your WiFi password contains special characters (quotes, backslashes, semicolons), double-check the generated code by scanning it immediately after generation. Some character combinations can cause unexpected results depending on the encoding.
When printing a QR code in 3D, use error correction level H. Print in two colours if possible — a light base with dark modules reads more reliably than a single-colour embossed print. Module height of 0.4–0.8 mm above the base tile gives good tactile definition and scanability. Always test the printed code with good lighting before distributing it.