# E.164 format

E.164 is the international phone number format: a plus sign, the country code and the national number with no spaces, up to 15 digits, e.g. +14155552671.

## What is E.164 format?

E.164 is the international phone number format: a plus sign, the country code and the national number with no spaces, up to 15 digits, e.g. +14155552671.

## Why you should use it

APIs and most sign-up forms expect E.164. Typing a number with the wrong country code is the most common reason a code never arrives.

Source: https://smsnitro.com/glossary/e164