How big should a QR code be for print?
The 10:1 rule, minimum sizes for cards, flyers and posters, and why short URLs scan better.
The 10:1 rule
A code should be roughly one tenth of the scanning distance. Someone holding a business card 15 cm away needs a 1.5 cm code; a poster read from 1.5 metres needs a 15 cm code.
Minimums by format
Business card: 1.5 to 2 cm. Table tent or flyer: 2 to 3 cm. A4 poster: 5 to 8 cm. Large poster or sign: 15 cm and up. These assume a short URL; long URLs need larger codes.
Why the URL length matters
Every character adds modules (the little squares). A 200-character tracking URL produces a dense grid that needs to be printed larger to scan reliably. A dynamic QR code contains a short redirect link, so the pattern stays sparse and scannable at small sizes.
Quiet zone and contrast
Leave a white margin at least four modules wide around the code. Use dark code on light background; inverted codes and low-contrast brand colours fail on many phones. Export SVG for print so the printer can scale without blur.