How big a QR code should be on a business card
Yes, a QR code fits on a business card. What it holds decides its size. A phone’s camera reads each square as dark or light, so each has to print large enough to tell from the one beside it. The figures come from the business card QR code generator, for a sample contact at the default error correction level, margin included.
| Content | Characters | Squares per side | Smallest width | Reads from about |
|---|---|---|---|---|
| Web address, 24 characters | 24 | 25 | 20 mm (0.8 in) | 20 cm (8 in) |
| vCard: name, mobile, email | 136 | 49 | 23 mm (0.9 in) | 23 cm (9 in) |
| + company, title, website | 196 | 57 | 26 mm (1.0 in) | 26 cm (10 in) |
| + second phone (a full card) | 231 | 61 | 28 mm (1.1 in) | 28 cm (11 in) |
| + street address | 300 | 69 | 31 mm (1.2 in) | 31 cm (12 in) |
| + a 64-character note | 372 | 77 | 34 mm (1.3 in) | 34 cm (13 in) |
The last column is a rule of thumb: a phone reads a code from about ten times its width. People scan a card from 15–30 cm (6–12 in), so every row is within reach. On a card the limit is the size of each square, not the distance. Shrink the full card’s code to 2 cm (0.8 in) and each square drops below 0.3 mm.
Why a vCard code needs more room
A vCard code holds the contact itself, so it carries far more characters than a web address, and the character count sets the number of squares (the standard calls them modules). A QR code is 21 squares a side at its smallest and grows 4 squares at a time, up to 177. At the same printed width, more squares means smaller squares.
As a rule of thumb, a safe floor for print is 0.4 mm a square. Under its preview the generator shows the character count, the squares per side and the smallest print width, which is never below 20 mm (0.8 in). The full sample card is 61 squares plus 4 of margin on each side: 69 squares at 0.4 mm, or 28 mm (1.1 in).
You can’t put every detail in the code and keep it small. To shrink it, cut characters. Leave out the street address and the note; the generator drops blank fields. Give one phone number, and type the website without https://.
The smallest option is a static code of a short web address, which still reads at about 1.5 cm (0.6 in). Static codes have no end date; do QR codes expire covers the kind that does. But this code holds only a link: the phone needs a connection, and the page has to stay up.
The quiet zone
The quiet zone is the empty margin around the code, and a phone uses it to find the code’s edges. ISO/IEC 18004, the QR standard, asks for 4 squares of plain background on all four sides. Both downloads from the generator include it. Don’t crop it. Set text, a border or the card’s cut edge against the code and the camera may not find where the code stops.
Error correction level
Error correction is spare data that lets a phone read a code when part of it is scratched or covered. There are four levels. A higher level and a smaller code work against each other, because each level adds squares. For the full sample card:
| Level | Squares per side | Smallest width |
|---|---|---|
| L, 7% | 53 | 25 mm (1.0 in) |
| M, 15% (the default) | 61 | 28 mm (1.1 in) |
| Q, 25% | 69 | 31 mm (1.2 in) |
| H, 30% | 81 | 36 mm (1.4 in) |
M suits most cards. Choose H when a logo sits over the middle of the code and covers squares the camera never sees.
Print and contrast
Print dark squares on a light background. Light squares on a dark card fail on some readers. The generator warns you when the code is lighter than its background or the two colors are too close.
Use the SVG download for print; it stays sharp at any size. The PNG is 1,024 × 1,024 pixels and stays sharp to about 8.5 cm (3.4 in) at 300 dpi. Keep the code square when you resize it.
Ink spreads on uncoated paper and fills small squares, so go above the minimum width there. Gloss, foil and spot varnish over the code cause glare. Before you order a batch, print one card at real size and scan it with two or three phones.
Where it goes on a 3.5 × 2 in card
A US card is 3.5 × 2 in (89 × 51 mm), and much of Europe uses 85 × 55 mm. Printers ask for about 3 mm (1/8 in) of safe margin from the cut edge; ask yours for the exact figure. On a US card a 28 mm (1.1 in) code takes more than half the height.
The back is the easier place for a full vCard code, because it has room for more than the minimum. A 20 mm (0.8 in) web-address code fits on the front.
Krane for iPhone
With Krane: the cards you're handed
Your code is on your card. Most cards you are handed have none. Krane on iPhone, iPhone Duo and iPad reads a printed card into a contact. On a card or badge with a QR code, it merges the code’s contact data with the printed details into one contact. The business card scanner is free for 10 scans a week.