"Pre-fill it with the given number, but not automatically initiate a call." That is how ZXing, the open-source barcode library, describes what a scanner should do with a phone number, and the official rules say the same. RFC 3966, which defines tel: links, says software must not place a call without the user's explicit consent. Apple's documentation says an iPhone shows an alert and asks for confirmation before dialling. A phone QR code puts your number in someone's dialler, and they decide whether to call.
What the code contains. The generator writes tel: followed by the number, keeping a leading plus and removing every other character that is not a digit. Type +61 2 9999 1234 and the code holds tel:+61299991234, 16 bytes, small enough for a 25 by 25 grid.
Three ways a phone code ends up with the wrong number:
- No plus. Without it the number stays in local form. RFC 3966 says a local number needs a
phone-contextparameter naming where it is valid, and this generator does not add one, so type the international form. - A bracketed zero. Numbers are often printed as +61 (0)2 9999 1234. The generator removes the brackets and keeps the zero, and
tel:+610299991234is not your number. Leave the zero out. - An extension. Letters are stripped and digits kept, so "ext 204" is glued onto the end of the number. Put the main line in the code and print the extension beside it.
Calls carry no tags. A tel: code hands the number straight to the dialler. No page loads, so there is nothing for UTM tags to report to, and no generator can count the scans. If you need the scans in your analytics, point a Link code at a contact page and tag it; the UTM guide for QR codes shows the values to use.
Printing it. A phone code is one of the smallest this generator makes. The minimum print width for tel:+61299991234 works out to 13.2mm (a 25 by 25 grid plus the clear margin, at 0.4mm a square), so a 20mm business card leaves room for a logo, even after the logo raises error correction to Q. At that size the panel's scan distance is about 20cm, roughly ten times the width, which suits a card held in the hand. For a sign read from across a room, use the Poster or Yard sign preset. Keep the Square pattern for print, and read QR code best practices for print before ordering cards in bulk.
The QR code reader decodes your downloaded PNG and shows the number a scanner will dial. To share your number along with your name, email and address, use the digital business card maker instead, and the click-to-chat link generator makes a tap-to-call link for a website or an email signature.