Maximum Length for International Phone Numbers

The following table shows how to calculate the safe maximum length for international phone numbers.

This table describes the maximum length for international phone numbers.

Is there a phone format for the country?

Then, the safe maximum length for international phone number is

Yes

C + 2N + E + 2 ≤ 40

No

2C + 2N + E + 2 ≤ 40

In the formulae in this table:

  • C is the length of the country code.

  • N is the length of the city code and the subscriber number, including any formatting, such as spaces or hyphens.

  • E is the length of the extension number.

The following table shows an example calculation of the maximum length of an international phone number (+834 91 518–400 x 123).

Example calculation of the maximum length of an international phone number.

International phone number

 Maximum length for each element (C, N, E)

+834

C=3

91 518–400

N=10

x 123

E=3