A contact QR code saves you to someone's phone in one scan. The trick on a card is space: a business card has little of it, and a contact card is a lot of data.
Keep only what people need
Every field makes the code denser. Name, mobile number and email are what most people save; a website and job title are nice to have. A full address and a note double the size of the code for something few people use.
| Format | Holds | Best for |
|---|---|---|
| vCard 3.0 | Name, company, title, phones, email, website, address, note | Most cards |
| MeCard | Name, phone, email, website, address, note | Small cards and short details |
How small it can be
A card is scanned from 15 to 25 cm, so by the ten-to-one rule of thumb a code of 2 to 2.5 cm is enough, as long as the content is short. Check the module size at your print width rather than guessing: below a few tenths of a millimetre per module, phones start to struggle.
On the command line
Write the vCard to a file, then let qrencode read it with -r:
qrencode -o card.png -s 10 -l M -r card.vcf
zbarimg --raw card.png
A vCard's lines end in CRLF, and zbarimg prints the card back exactly as it is
in the file.
- Choose the fields people will really save.
- Make the code as vCard, or as MeCard when it has to be very small.
- Set the print width and check the module size and the scan badge.
- Leave the margin around the code clear on the card design.
- Print one card and scan it with two phones before you order the box.
