E.164 Phone Number Format: Examples and CSV Import Guide
Learn E.164 phone number format with country examples, extension handling and a practical CSV import workflow. Preserve country context and review numbers that cannot be normalized.
OwnerClue · Updated
E.164 gives a phone number a consistent international form: a plus sign, a country calling code and the national number, with a maximum of 15 digits. For example, a US number written as (202) 555-0123 becomes +12025550123. The plus sign does not count toward the 15-digit limit.
For a business list, the useful outcome is a phone column that survives CSV export and CRM import without losing its country code. Keep the original number alongside the normalized value so you can review mistakes.
What is E.164 phone number format?
The common stored representation is:
+[country calling code][national significant number]
The country calling code contains one to three digits. The national number includes an area code where the country's numbering plan uses one. Store the result without spaces, brackets or hyphens; keep an extension in a separate field. Twilio's E.164 explanation describes this international structure and its 15-digit maximum.
A country calling code is different from a country abbreviation. GB is a country code used by many software libraries; +44 is a telephone calling code. A calling code can also cover multiple countries or territories: +1 does not identify the United States alone.
E.164 examples by country
These examples illustrate formatting. They are not verified contact records or numbers to call.
| Country | Number as written locally | E.164 representation | What changes |
|---|---|---|---|
| United States | (202) 555-0123 | +12025550123 | Add +1 and remove punctuation |
| United Kingdom | 020 7946 0018 | +442079460018 | Replace the national trunk prefix 0 with +44 |
| Brazil | (11) 91234-5678 | +5511912345678 | Add +55 and retain the area code 11 |
| Italy | 06 1234 5678 | +390612345678 | Add +39 and retain the significant leading 0 |
The Italy example explains why “remove every leading zero” is an unsafe conversion rule. A zero can be a domestic dialing prefix in one country and part of the number in another. Identify the country and parse its numbering rules before removing digits.
Convert a business phone list without guessing
Start with a small sample containing international numbers, local numbers, extensions and missing country values. Use a country-aware parser rather than a formula that simply deletes punctuation and adds +1.
- Preserve the input. Keep the original phone string, its published source and any location evidence. If a spreadsheet has already removed a leading zero, return to the source instead of inventing it.
- Establish country context. Use the business location or an explicit international calling code. A national number without a reliable country belongs in a review queue. The country where you are importing the file is not necessarily the number's country.
- Separate the extension. A main number with “ext. 204” has one E.164 base number and a separate extension value. Do not append 204 to the base number.
- Normalize with the country rules. Already international numbers should retain their calling code. Local numbers require the appropriate country context. Check ambiguous results rather than accepting every plausible output.
- Retain unsuccessful rows. Mark missing, ambiguous or unrecognized numbers for review. Keep a reason so a later import does not silently discard those businesses.
- Test the destination. Import a few records, inspect the resulting fields and export them again. Confirm that the plus sign, all digits and extensions survive the round trip.
A review table can use the following columns. These are suggested spreadsheet fields, not a promise about any product's export schema.
| raw_phone | country_context | e164_phone | extension | review_reason |
|---|---|---|---|---|
| (202) 555-0123 ext. 204 | US | +12025550123 | 204 | |
| 020 7946 0018 | GB | +442079460018 | ||
| 020 7946 0018 | Unknown | Confirm country before converting |
Do not merge company records solely because their normalized phone matches. Several branches may use one central line. Extensions can identify different destinations behind the same switchboard.
Extract and normalize numbers from pasted text
Use the free phone number extractor when your starting point is text containing phone numbers:
- Paste the text and select the default country for numbers written in a local format.
- Extract, then inspect the normalized international numbers and any separate extensions.
- Copy the results or download the CSV, which includes the original matched text, normalized number, country and extension.
The tool processes up to 100,000 characters in your browser. Different spellings of the same number are merged; different extensions remain separate. For mixed-country text, use explicit international numbers or process local formats in separate groups with the correct country selected.
The extractor returns recognized matches. It does not retain every original spreadsheet row or produce an error row for each unrecognized string. Keep your source file when the job requires reconciliation of a whole CRM table.
Keep phone numbers as text in Excel and CSV
A CSV file has no column types. Quotation marks around a phone value do not guarantee that a spreadsheet will preserve it as text. Opening a CSV directly can trigger automatic number conversion, removing a plus sign or displaying long values in scientific notation.
In Excel, import through Data → From Text/CSV and set phone columns to Text before loading. Use Transform Data when necessary and remove automatic numeric conversion for those columns. In other spreadsheet tools, use a text-preserving import or paste workflow and inspect the imported values before saving.
Store the actual value as +12025550123. A leading apostrophe can act as a spreadsheet entry marker, but it must not become part of the phone string sent to your CRM. After exporting to CSV, import it again with phone columns treated as text and compare a few full values.
Follow the receiving platform's field rules. For example, Google Ads' phone formatting guidance explains international phone formatting for its own uploads. A correctly formatted phone column does not satisfy unrelated requirements such as customer matching eligibility or permission to contact someone.
Formatting, validation and reachability are different checks
This regular expression is a coarse shape check:
^\+[1-9]\d{1,14}$
It accepts a plus sign followed by 2–15 digits, with the first digit nonzero. It does not check whether a calling code exists, whether a national prefix is valid, or whether the number belongs to a business. Passing it is insufficient to establish a valid telephone number.
A country-aware library can check length and prefixes against numbering-plan metadata. That still does not prove current assignment, active service, SMS capability, ownership or consent. An E.164-looking value is not evidence that it reaches the business owner.
When building a list from Google Maps business data, treat a published phone as a business contact path. It may reach a reception desk or shared office line. Keep the source and collection time, and read how OwnerClue distinguishes sources and verification before importing. The GoHighLevel CSV workflow explains the existing handoff and field mapping.
Frequently asked questions
Does every E.164 number have the same length?
No. The maximum is 15 digits excluding the plus sign. Acceptable lengths depend on the relevant numbering plan; the example regex's two-digit minimum is only its own syntax rule.
Can I include an extension in E.164?
Keep it separate. Import the base number into the phone field and the extension into a supported extension field or a clearly labeled note. Appending extension digits changes the number.
Can I replace 00 with a plus sign?
Only when you know 00 is the international access prefix used in the input's dialing context. International access prefixes vary. Do not universally strip 00 or assume that any leading digits are a country calling code.
Why did my phone number change in Excel?
The column was likely interpreted as numeric data. Reimport the original CSV with the phone column set to Text. Changing the display format afterward cannot reliably restore digits already lost.
Is a country required if the number starts with +?
An explicit international number usually supplies its calling code. A local-format number needs country context. Neither a plus sign nor a library validation result confirms that the number is active or appropriate for outreach.