How a phone number QR code works
The code contains a tel: link, the same kind a “Call us” button uses on a website: tel:+14155552671. Spaces, dashes and brackets are removed, and only digits and a leading plus sign are kept.
When scanned, the phone shows the number and offers to call it. On iPhone the Camera app displays a banner; on Android the camera or Google Lens shows a call button. The phone never dials by itself; the person always confirms. The code is among the smallest you can make, so it scans easily even when printed small.
Because only digits and the plus sign are kept, extensions and pauses written as commas or “ext.” are dropped. If callers need an extension, print it next to the code.
Where it helps
- A plumber's van carries a large code on the side, so someone stuck in traffic behind it can save the call for later without writing anything down.
- A “For sale” sign in a car window opens a call to the seller, which is safer than squinting at a number while walking past.
- A clinic's appointment card links to the booking line, reducing misdialed calls.
- An apartment building posts the property manager's emergency number as a code in the lobby.
Tips before you print
- Write the number in international form, starting with + and the country code, so it works for visitors and roaming phones.
- Print the number as text beside the code as well. Some people prefer to dial, and it helps anyone without a camera.
- For vehicles and outdoor signs, size the code for the real viewing distance: roughly one tenth of the distance, so 30 cm (12 in) for someone 3 m away.
- Use the SVG file for vinyl lettering and large signs so the edges stay sharp.