E.164: the international phone format explained

E.164 is the international standard, published by the ITU, that defines how a phone number should be written to be routable anywhere in the world. In its full form, an E.164 number looks like this:

+[country code][subscriber number]

No spaces, no dashes, no parentheses, no leading zeros. Just a plus sign, a country code (1 to 3 digits), and the local number. The whole thing must be at most 15 digits after the plus.

How US and Canadian numbers work in E.164

Both the US and Canada share country code +1. Every North American number written in E.164 is:

+1 + 3-digit area code + 7-digit subscriber number

Examples:

• San Francisco: +14155552671
• New York: +12125551234
• Toronto: +14165551234
• Vancouver: +16045551234

Why the format matters

Every phone system in the world — WhatsApp, SMS gateways, VoIP switches, CRM software, contact-syncing apps — treats E.164 as the canonical format. If your database stores numbers in mixed local formats ((415) 555-2671, 415.555.2671, 4155552671) instead of E.164 (+14155552671), three things break:

• Duplicates multiply. The same subscriber might exist in your database three times under three different formats.
• Deliverability drops. SMS gateways silently discard messages sent to non-E.164 numbers when the sender's country is ambiguous.
• International routing fails. A call originating outside North America to (415) 555-2671 has no country to route to.

Converting local to E.164

The rule for converting a US or Canadian local number:

1. Strip everything that isn't a digit — no parens, no spaces, no dashes.
2. Drop the leading 1 if the number was written as "1-415-555-2671".
3. Prepend +1.

Example: (415) 555-2671 → strip → 4155552671 → prepend +1 → +14155552671.

What our verifier returns

When you look up a number on Verify Phone Number 1, the result includes an "E.164 format" field. That's the canonical form — the one you should store in databases, CRMs, and messaging systems.