---
title: "What is E.164?"
url: "https://lookvalid.com/glossary/e164.md"
canonical_url: "https://lookvalid.com/glossary/e164"
last_updated: "2026-10-23"
type: "conceptual"
summary: "E.164 is the international format for phone numbers."
related: ["https://lookvalid.com/glossary/nanp.md", "https://lookvalid.com/glossary/area-code.md", "https://lookvalid.com/glossary/line-type.md", "https://lookvalid.com/products/phone.md"]
---

# What is E.164?

E.164 is the international format for phone numbers.

E.164 is the international format for phone numbers: a plus sign, the country code, then the national number, with no spaces or punctuation and at most 15 digits.

Because it is unambiguous, E.164 is the form to store in a database and to send to an API. A US number written as (415) 555-0123 becomes +14155550123.

Display formats such as national and international styles are generated from the E.164 value when a person needs to read it.

Validating against E.164 checks structure: the plus sign, a real country code and a length of 15 digits or fewer. Passing means the number is well formed, not that anyone answers it, so pair it with a line-type or carrier lookup before you send a message or place a call. Strip spaces, dashes and brackets before storing, and keep the leading plus so a country code cannot be mistaken for a local prefix.

## Related

- [What is NANP (North American Numbering Plan)?](https://lookvalid.com/glossary/nanp.md)
- [What is Area code?](https://lookvalid.com/glossary/area-code.md)
- [What is Line type?](https://lookvalid.com/glossary/line-type.md)
- [Phone Numbering-Plan Validation API](https://lookvalid.com/products/phone.md)