The E.164 number format is an internationally recognized standard that ensures every phone number on the Public Switched Telephone Network (PSTN) is globally unique and consistently structured. Aircall requires this format to ensure accurate call routing, seamless integrations, and reliable contact synchronization.

What the E.164 format is

E.164 is defined by the International Telecommunication Union (ITU) and specifies the following rules:

  • Structure: + country code area code subscriber number
  • Maximum length: 15 digits
  • No spaces or special characters: The number must not include spaces, parentheses, or dashes.

Examples:

  • UK number 020 1234 5678 becomes +442012345678
  • US number (415) 123-4567 becomes +14151234567

Why this format matters

Using the E.164 standard helps ensure:

  • Accurate call routing to international and domestic destinations
  • Compatibility with integrations such as CRMs and helpdesks that require E.164 numbers
  • Correct contact matching for features like Contact Sync
  • Error-free operations, reducing failed calls, duplicate contacts, and missing logs

Key features overview

  • Global uniqueness: Each number is globally identifiable
  • Standardized structure: Ensures consistent processing across systems
  • Integration ready: Required by many third party tools
  • Improved reliability: Minimizes formatting related call issues

How to configure E.164 numbers

1. Manual entry

When adding contacts manually in Aircall, enter numbers directly in E.164 format, including the + and country code.

Example:
French number 06 12 34 56 78 becomes +33612345678.

2. Using Google Sheets

You can convert large sets of numbers using spreadsheet functions:

  • REGEXREPLACE to remove non digit characters and add a country code
    • Example for France:
      ="+33"&REGEXREPLACE(A1,"\\D","")
  • REPLACE to remove leading zeros or prefixes
    • Example to remove one leading zero:
      =REPLACE(A1,1,1,"")

3. Bulk import

Before importing contacts into Aircall, make sure all phone numbers in your CSV are already in E.164 format.

Frequently asked questions

Can I use spaces or dashes in an E.164 number?

No. E.164 numbers must be a continuous string starting with + and digits only.

What happens if I do not use E.164?

You may experience failed calls, incorrect routing, duplicate or unmatched contacts, and integration issues.

Is E.164 required for all Aircall features?

Some features may accept other formats, but E.164 is strongly recommended for full compatibility and best performance.

How do I convert existing numbers into E.164?

Use tools like Google Sheets with functions such as REGEXREPLACE and REPLACE to standardize numbers efficiently.