Phone Number Formatter

Paste one phone number or a whole column from a spreadsheet, choose the default country and the output style, and get consistently formatted numbers — E.164 for software and SMS tools, international format for business cards and websites, or local formats for printed lists. Numbers that do not look valid are flagged for checking.

Phone number formats explained

E.164 is the international standard from the ITU: a plus sign, the country code and the national number, with no spaces or punctuation, up to 15 digits in total. Storing numbers in E.164 makes them unambiguous; you can always display them in a friendlier format later.

How the formatter works

1. Strips spaces, brackets, dashes and dots, and separates any extension (ext., x or #).
2. If the number starts with + or 00, reads the country code from it; otherwise uses the default country you select.
3. Removes a leading 1 from 11-digit North American numbers and the trunk prefix 0 used for domestic dialling in countries such as the UK, Australia, Germany and France.
4. Checks that the remaining national number has a plausible length for that country.
5. Groups the digits for display according to the chosen format.

The check is a sanity test for length and obvious errors, not full validation. Numbering plans are complex — area codes, mobile ranges and number lengths vary within countries — so numbers flagged as OK can still be unassigned, and a few unusual valid numbers may be flagged for checking.

Trunk prefixes and country codes

Many countries use a trunk prefix — usually 0 — when dialling within the country, but drop it when dialling from abroad. A London number is written 020 7946 0958 domestically and +44 20 7946 0958 internationally. North America uses 1 as both the country code and the long-distance prefix, so 1-212-555-0198 and +1 212 555 0198 are the same number. Italy is an exception: the leading 0 of landline numbers is kept after +39. The formatter handles these cases for the listed countries.

Cleaning a contact list

• Copy the phone column from your spreadsheet and paste it into the box.
• Choose the country most of your contacts are in as the default.
• Pick E.164 if the list is going into a CRM, email platform, SMS tool or phone system.
• Copy the results and paste them back into a new column next to the original, so you can compare.
• Filter the “Check” column for flagged numbers and fix them manually.
• Remove duplicates after formatting — numbers that looked different often turn out to be the same.

Worked example

A sales team exports 2,000 contacts with numbers typed in many ways: “(555) 123-4567”, “555.987.6543”, “+1 212-555-0198”, “1-800-555-0100 ext. 22” and some UK numbers such as “020 7946 0958”. With the default country set to the United States and E.164 output, the US numbers become +15551234567, +15559876543, +12125550198 and +18005550100;ext=22. The UK number without a code is flagged, so the team sets the country to UK for those rows, giving +442079460958. The entry “12345” is flagged as too short for review.

Common input problems

Spreadsheets often convert phone numbers to numbers, dropping leading zeros and adding decimals. Format the column as text before typing or importing numbers to avoid this.

Formatting for websites

On websites, display the number in international or national format for readers, and use E.164 in the link so it can be dialled on phones: <a href="tel:+12125550198">+1 212 555 0198</a>. For WhatsApp click-to-chat links, the number is written without the plus sign or punctuation. Consistent formatting also helps search engines and customers recognise your business contact details.

Test and fictitious numbers

Examples on this page use ranges set aside for fiction and documentation, such as 555-01xx numbers in North America and the Ofcom drama ranges in the UK (020 7946 0xxx, 07700 900xxx). Use similar ranges when you need sample data in documentation or testing.

Spreadsheet alternatives

For a quick fix inside a spreadsheet, a formula can strip punctuation — for example, nesting SUBSTITUTE to remove spaces, dashes, dots and brackets — and then prefix the country code. That works for lists from a single country with consistent input. Mixed international lists are easier to handle here, because the formatter reads country codes and trunk prefixes line by line.

Privacy

Formatting happens entirely in your browser. The numbers you paste are not uploaded, logged or stored — close the page and they are gone. That makes it suitable for customer lists that should not be shared with third-party services.