E.164 Phone Number Validator

Paste a number to check it against the E.164 format. If it fails, you'll see why.

Got a whole list to fix? Use the bulk phone number formatter.

What is E.164 format?

E.164 is the ITU's standard for writing phone numbers so any system in the world reads them the same way. Every E.164 number follows one pattern:

+[country code][subscriber number]

  • Starts with +
  • Country code of 1–3 digits that never starts with 0
  • Digits only: no spaces, dashes, dots or brackets
  • 15 digits at most, country code included
  • No national trunk prefix (the leading 0 used for domestic calls in the UK, India, Australia and others)

As a regular expression: ^\+[1-9]\d{1,14}$

E.164 examples by country

Country Written locally E.164
United States (415) 555-2671 +14155552671
United Kingdom 020 7946 0018 +442079460018
India 098765 43210 +919876543210
Canada (604) 555-0199 +16045550199
Australia (02) 5550 1234 +61255501234
Germany 030 123456 +4930123456
Nigeria 0803 123 4567 +2348031234567

Writing numbers for people rather than systems? That's E.123, with spaces. See E.164 vs E.123.

Your numbers live in Google Sheets?

Validate a whole column with a formula, then send SMS to it with TwilioBox, which expects E.164.

Validate in Sheets → See TwilioBox

Frequently Asked Questions

What is E.164 format? ▾
E.164 is the international phone number standard from the ITU. A number is written as a plus sign, the country code, then the subscriber number, with no spaces, dashes or brackets, and at most 15 digits in total. For example, +14155552671.
What is an example of an E.164 phone number? ▾
A US number (415) 555-2671 becomes +14155552671. A UK number 020 7946 0018 becomes +442079460018: the leading 0 is dropped and +44 added. The table on this page has more countries.
How do I convert a number to E.164? ▾
Remove spaces, dashes, dots and brackets. Remove the national trunk prefix (usually a leading 0). Add + and the country code in front. To do this for a whole list at once, use the phone number formatter.
Is a valid E.164 format the same as a real phone number? ▾
No. This checks the format only: plus sign, digits, length. A number can be perfectly formatted and still be unassigned or disconnected. Checking that needs a carrier lookup.
What's the difference between E.164 and E.123? ▾
E.164 is the machine format with no spaces, used by APIs, databases and SMS providers like Twilio. E.123 is the human-readable format with spaces, like +44 20 7946 0018, meant for business cards and websites.
Is my number sent anywhere? ▾
No. Validation runs in your browser. Nothing you type is uploaded or stored.

You Might Also Like

API for GTM Engineer: Infographics

Productivity

A visual breakdown of how APIs work for GTM engineers, covering core concepts, common integrations, and where automation fits into your marketing stack.

Case Study: 3Sum (LeetCode 15)

DSA

A real attempt-by-attempt debugging journey through LeetCode 15 with the Two Pointers pattern.

Two Pointers Pattern

DSA

Master the Two Pointers technique with a story, visualizer, and TypeScript code for palindromes and pair-sum problems.

View All Tools View All Resources View All Blog Posts