QR code size, contrast and print guide

A QR code that looks fine on screen can fail badly once it is printed. Small size, low contrast, a crowded margin or the wrong material are the usual causes. This guide covers the practical rules for printing codes that scan reliably.

How big should a QR code be?

The right size depends on how far away people will scan it and how much data it holds. A widely used rule of thumb is a distance-to-size ratio of about 10 to 1: a code scanned from 1 metre away should be roughly 10 centimetres wide. Codes that hold a short URL have larger, simpler modules, so they scan well even when fairly small.

• Business card or product label, scanned by hand: at least 2 cm wide.
• Table tent or flyer, scanned from arm's length: 3 to 5 cm.
• Poster on a wall, scanned from a few metres: 10 cm or more.
• Billboard or shop window: scale up in proportion to the distance.

Keep the quiet zone clear

The quiet zone is the empty margin around the code. The standard recommends at least four modules of blank space. Text, borders or busy backgrounds that crowd into this area confuse scanners about where the code begins. When you design a layout, treat the margin as part of the code.

Contrast matters most

Scanners look for the difference between dark and light modules. Black on white is the safest combination. Dark blue or dark green on white also works. Avoid light-on-dark inversions unless you have tested them, because some older scanners cannot read them, and avoid pastel colours that reduce contrast.

• Make the code clearly darker than its background.
• Do not place the code over a photograph or gradient.
• If you brand the code with colour, check it still scans in dim light.

Error correction and logos

Putting a logo in the middle of a code hides some modules. This is only safe if error correction is high enough to recover them, which usually means level Q or H. Higher error correction makes the pattern denser, so increase the printed size to compensate, and keep the logo small.

Choose the right material

Matte finishes are best. Glossy paper, foil and shiny plastic reflect light and can blind a phone camera. Curved surfaces like bottles distort the pattern; make the code smaller relative to the curve or place it on the flattest part. On textured materials such as rough cardboard, increase size and contrast.

Resolution and file format

For print, export the code as a vector file (SVG or PDF) when possible so edges stay sharp at any size. If you must use a raster image, use a high resolution and never scale it up after export. Fuzzy edges make modules harder to distinguish.

Test before you print a large batch

Print one copy at the real size on the real material and scan it with at least two phones, in the lighting where it will be used. Try it from the actual scanning distance. A five-minute check before printing thousands of copies is the cheapest insurance you can buy.

• Scan from the intended distance and angle.
• Test on both iPhone and Android.
• Test in bright light and in dim light.
• Confirm the destination page loads quickly on mobile data.