Phone number formatter (E.164)

Updated 2026-09-30 · By the ZuteSIP team (ZuteSIP Inc.)

Short answer: To convert a phone number to E.164, remove spaces, dashes and brackets, drop the national trunk prefix (usually a leading 0), then add + and the country code. For example, the UK number 07700 900123 becomes +447700900123. The formatter below does this for 181 countries.

Paste a number the way you'd write it locally, choose the country, and the tool returns the international E.164 version and checks the digit count.

How to format a number by hand

1. Remove everything that isn't a digit: spaces, dashes, dots and brackets.
2. If the number starts with the country's trunk prefix (0 in most of Europe, Asia and Africa), remove it.
3. If it already starts with the international access code (00 or 011), remove that too.
4. Put + and the country calling code in front.
5. Check the length: at most 15 digits after the +.

Examples

Why E.164 matters

Apps such as WhatsApp and Telegram, SIP systems and SMS gateways store numbers in E.164. A number saved in local format may fail to receive verification codes or may not match your contacts when you travel.

Frequently asked questions

What does the formatter check?

It removes formatting characters and the trunk prefix, adds the country code, and compares the number of digits with the usual national number length for that country.

Does it tell me if a number is active?

No. It checks the format only; it doesn't look the number up on any network.

Is my number sent anywhere?

No. The formatting runs entirely in your browser.

Where do I find a country's code?

See the full list of 181 countries on the country calling codes page.

Related pages

• Country calling codes (181 countries)
• What is E.164?
• Phone numbers by country
• SIP dialer setup
• Pricing
• Verification code not received?

Sources

• ITU-T Recommendation E.164 (as of September 2026)