One number.
Five useful formats.

The right format depends on where your contact list is going. E.164 is a practical default for international lists. Check your destination system’s requirements before importing.

The numbering standard is ITU-T E.164: The international public telecommunication numbering plan. It describes the structure of international telephone numbers; the examples here show how E164flow applies formatting in an import workflow.

Choose the country before guessing.

National numbers need a default country. For a mixed-country spreadsheet, map a column with two-letter ISO codes, such as GB, SI or US. An explicit international prefix takes priority. An empty country cell uses your default; an invalid ISO code needs review.

Check the import preview.

For CSV and Excel files, we examine up to 100 sampled rows across the file to suggest phone fields and a country column. Explicit international numbers can identify a phone field even when its header is unclear. Digits alone can also be IDs, so uncertain fields require manual selection. The suggestions help select fields; they do not validate the complete list.

Review the original values, selected phone fields and country settings before confirming the import. You can show all source columns in the preview. A missing country is never inferred from phone prefixes, and multiple possible country fields need your choice. Changing the file, worksheet, column mapping or default country requires a fresh confirmation. Saved profile fields that are missing are shown explicitly and are not replaced automatically.

Check several phone fields together.

Select up to 10 phone columns, such as Phone, Mobile and Work phone. Results identify the source row and column. Exports keep one row per original contact, with separate generated fields for each selected phone column. If an export filter excludes a phone cell, its generated fields are blank; the original fields stay in the report.

Review before exporting.

Ready means the number passes numbering-rule validation without an unresolved important warning. Needs review means its format is valid, but a numeric source, conflicting country or other important warning needs checking. Invalid means it cannot be converted safely. The default export includes Ready numbers only. You can select All numbers for the full report.

Select phone cells to set their country together, restore original inputs, or mark valid numbers as checked after comparing them with the source. International prefixes still take priority. Checking a number does not make an invalid number valid and does not confirm that it is active.

Keep extensions separate.

We accept ext. 123, x123, int. 123 and ;ext=123. Extensions are exported in a separate column because they are not part of E.164. Two numbers with the same base number but different extensions are not marked as duplicates.

The phone-link syntax and separate extension parameter are specified in RFC 3966, The tel URI for Telephone Numbers. For example, the extension in tel:+442079460018;ext=007 is separate from the base number.

Protect leading zeros.

Store phone cells as text in your spreadsheet. If Excel has already removed a zero, no formatter can reliably restore it. Numeric sources get a warning. Text in scientific notation is rejected so rounded or incomplete numbers do not silently enter your list.

Choose the fields your destination needs.

Open Customize export columns to select fields, rename headers and change their order. The CRM columns shortcut includes clean E.164 phone fields and separate extensions. Select your record ID field when updating existing contacts; it stays included and keeps its original text values. Verify that the chosen ID matches the destination’s contact identifier.

The file preview shows the first three selected contact rows with the actual headers, order and format. Local profiles can save the export layout for your next file. They save settings and column names on this device, never contact rows or file contents. If a saved field is missing, update the layout before exporting.

Export with confidence.

Excel exports use text cells to preserve + signs and zeros. Spreadsheet-safe CSV adds an apostrophe to values that could be read as formulas, including values beginning with +. CRM CSV preserves + in generated E.164 and Output fields, including renamed fields; original fields and headers remain escaped. Import CRM CSV directly into your destination without opening and resaving it in Excel. Use Excel for exact text, or verify your importing system’s CSV handling.

What “valid” tells you.

A valid result matches the numbering rules in our included metadata. It does not confirm ownership, reachability or consent to contact someone. Short emergency codes, alphabetic numbers and multiple numbers in one cell are outside the standard contact-number workflow.

What happens in each account state?

Without an account, you can paste up to 25 numbers for a preview; files and exports stay locked. A free account adds CSV/XLSX input, export, saved defaults and a 50-row limit. Pro unlocks the complete workflow for up to 20,000 rows per file. All three states use the same local processing path.