In depth
What a tel: link looks like
A tel: link follows RFC 3966. For a global number it is the plus sign, the country code and the digits. Hyphens, dots and brackets are allowed as visual separators, but spaces are not, so the generator uses the plain form. An extension becomes a ;ext= parameter. These are real results.
| You typed | tel: link |
|---|---|
| +44 20 7946 0958 | tel:+442079460958 |
| (650) 253-0000 ext. 123 (US) | tel:+16502530000;ext=123 |
| 020 7946 0958 (GB) | tel:+442079460958 |
| +1 800 555 0199 | tel:+18005550199 |
Always include the country code
RFC 3966 says numbers should be written in global form whenever possible. A local number such as tel:7042 only works if the link also says in which context it is valid, which web pages almost never do. A global number with its country code works for every visitor, wherever they are.
Making the link good for users
- Show the number as the link text, so people on a desktop, where nothing may happen when they click, can still read and copy it.
- Use the international display format for the text, for example +44 20 7946 0958, and keep the href in the plain E.164 form.
- Do not use callto:. It is a legacy scheme from Skype and is not part of RFC 3966.
- Do not put the link on an image without a text alternative. Screen readers need words.
What happens when someone clicks
On a phone the link opens the dialler with the number filled in, and the user still has to press call. On a computer it opens whatever calling app is set up, such as FaceTime or Teams, or nothing if there is none. Test the link on both.
Examples you can paste
A simple call link, and one with an extension. The href stays in the plain form, while the visible text is formatted for people.
<a href="tel:+442079460958">+44 20 7946 0958</a>
<a href="tel:+16502530000;ext=123">+1 650 253 0000 ext. 123</a>In email, print and apps
Most email apps and phones also turn a plain number in the text into a link on their own, which is why a clear international format helps. In print, show the number with its country code so readers abroad can dial it.