E164 telephone number format
What is the E164 telephone format and how should you prepare phone numbers for importing?
Written by Andrew Belbin
Updated over a week ago

What is E164?

E164 is an international standard for both mobile and landline telephone numbers. It ensures that any phone anywhere in the world can receive a call or text because it ties it to the Country that the number belongs to using an international dialing code. An E164-formatted telephone number looks like this:

Mobile: [UK flag emoji] +44797352188

Why does E164 matter?

Simply put, if a number doesn't include the country's dialling code, it's likely you won't be able to contact the student via phone or SMS.

For example, a student may have the mobile number "07973 521888". This is automatically formatted by the platform based on their country. If the student has an American or French address, the platform will automatically add the dialling codes for those countries, even if the student's number is English. Therefore you must add the correct dialling code otherwise the American or French numbers will not work:


  • If you use the Student CRM E164 formatted tel numbers for voice calls, it will work.

  • If you use the Student CRM E164 formatted tel numbers for SMS, it will work.


Q. Is this the same as I see on my mobile phone?

A. Yes. Your phone also uses E164 formatting to know which country the person you are calling lives in.

Q. Why don't I need to format my telephone numbers as E164 in the CSV template?

A. Because it is automatically formatted by Student CRM, based on the Country. You don't need to do anything other than use the number you have and add the Country value into the Country field(s).

Q. What if my telephone numbers are already E164 formatted?

A. No problem, that will work. Because E164 already carries a country identifier, and the number is evaluated against that, the Country value into the Country field(s) are not used to format the telephone number.

Q. Can Excel mess up E164 formatting?

A. Yes, it can. The best way to avoid this is to always work in a 'CSV' file format when preparing your data. As soon as you save the file or change it to an 'XLS' file format, Excel tries to help, which can corrupt telephone numbers.

Q. After an import, some rows were rejected. How can I tell if it was the telephone number?

A. If you download the Rejects file, at the end of each row there will be an error message explaining what went wrong and how to fix it, like this example error message:

Invalid phone number provided ([phone number])

Check that the phone number: is prefixed by a type (eg "work"); has a "+" in front of the country code (eg "+44"); is using a correct country code (eg "44"); has no more than 15 digits.

Q. Where can I find out more technical info about E164 formatting?

A. Check out the Wikipedia article here.

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