Bulk phone-number formatting without a data upload
Turn a mixed-country contact list into a consistent format in your browser, with validation, duplicate review and a clean export.
When a contact list comes from several countries, the hard part is usually the small inconsistencies: spaces, trunk prefixes, country columns, extensions and duplicate records. E164Flow gives you a repeatable local workflow for cleaning that list before it reaches a CRM or sales tool.
How do I start this workflow?
Keep the source file, confirm the phone and country fields, and review the results before choosing the import layout.
- Choose the default country, or map a country column.
- Paste numbers or load a CSV/XLSX file and review the source rows.
- Inspect invalid values and duplicates, then export the full, unique or filtered result.
What does a mixed-country file look like after formatting?
Keep the original record ID and country beside the generated E.164 value. The examples below show formatting outcomes, not live checks of the demonstration numbers.
| Record ID | Original phone | Country | Result to review |
|---|---|---|---|
| 101 | 020 7946 0018 | GB | +442079460018 |
| 102 | 041 123 456 | SI | +38641123456 |
| 103 | +44 20 7946 0018 ext. 007 | GB | +442079460018; extension 007 |
| 104 | 020 7946 0018 | Empty | Choose country context before converting |
Rows 101 and 103 share a base number, but the extension changes the destination. Keep the source ID attached to each row instead of replacing contact identity with a formatted phone number. An empty country is acceptable for an explicit international number; a national number needs a mapped country or a deliberate default.
Should I choose one default country or map a country column?
Choose one default only when the national numbers belong to the same country. For a mixed list, map the country column and review missing or conflicting values.
A country selection supplies context for values such as 020 7946 0018. It is not an instruction to replace an existing international prefix. If a source row already says +386, a default of GB does not turn that number into a British number. The prefix takes priority, and conflicting source context can produce a review warning.
Start with a small sample containing every country represented in the file. Include an empty country cell and a national number in that sample so you can check how the default applies before processing the complete list.
How do I format Phone, Mobile and Work phone together?
Select the relevant phone fields in the import preview. E164flow supports up to 10 selected phone columns and keeps the export aligned to the original contact rows.
Do not duplicate a contact into a separate spreadsheet row just to check another phone field. Each result identifies its source row and source column, so you can distinguish a problem in Mobile from a problem in Work phone. Generated export fields are separate for each selected phone column.
Suggestions help locate phone columns but do not replace your decision. Review the sampled source values, selected worksheet and header row. A column of customer numbers may resemble telephone data, and an unfamiliar header may contain genuine phone numbers. Confirm the mapping before starting the full conversion.
Which results can I export without another review?
The default export uses Ready results. Needs review identifies a value whose numbering format may be valid but whose source or context still needs checking.
For example, a phone stored as a numeric spreadsheet cell can lose useful source information, while a country field may disagree with an explicit international prefix. Read the row's warning and compare the original input with the generated value. A valid format alone is not enough to dismiss that warning.
Use a correction only when the source supports it. You can update selected phone cells together, restore their original inputs, or acknowledge a checked valid number. Rechecking recalculates duplicate references. Acknowledging a row does not make an invalid number valid or confirm that it is reachable.
Does a duplicate phone mean I should delete a contact?
No. A duplicate reference means phone values match within the processed list; it does not establish that the contact records are the same person.
Two contacts may legitimately use a shared office number. A contact may also repeat the same number in Phone and Mobile. Review the source IDs and the source columns before choosing a unique-number export. The first matching number is not automatically the correct business record to keep.
Extensions remain separate from the base E.164 number. Numbers with different extensions are not treated as the same endpoint by the extension-aware duplicate check. When importing into a CRM, retain its contact identifier and decide which phone field to update rather than using the duplicate list as an instruction to merge CRM records.
How should I prepare the final columns for an import?
Use the CRM columns shortcut when you need a focused layout of record IDs, E.164 phone fields and extensions. Rename and order the headers to match the destination.
Keep a full report for review when you need the original values, validation details or duplicate references. The filtered export can contain fewer results than the complete review table. On a contact row included in a multi-column export, a filtered-out phone cell has blank generated output while the other included fields remain available.
Check the file preview before downloading. It shows the first selected contact rows with the actual column order and headers. Confirm the record ID field, the number of contact rows and the export selection. Then test a few records in the destination before replacing a larger set of existing values.
What limits and privacy rules apply to a repeated cleanup?
The guest preview accepts 25 pasted numbers, a free account handles files up to 50 rows, and Pro handles up to 20,000 rows per file. Contact conversion runs in your browser.
A local import profile can save the settings you repeat, including mapping and export layout. It does not save contact rows. A new file still needs review: a supplier can change a header, move a country field or add a second worksheet without changing the filename.
Keep the source file and the reviewed export under your own file-management process. The current contact list disappears when the page is cleared, reloaded or closed. Browser-local processing is separate from account, preference and billing requests; it does not mean that sign-in or subscription management happens offline.
Which primary sources support this workflow?
Use the underlying standard or the destination's own documentation when checking a numbering rule or an import requirement.
What should I check before the final import?
Compare a small sample with the source and the destination, then use this checklist to review the complete file.
- Keep source columns beside the generated E.164 value.
- Review rows with ambiguous or missing country information.
- Keep extensions in their own column when importing into another system.
- Use the CRM CSV option only after confirming how your destination handles text values.
Start with the data you have.
Use 25 pasted rows without an account, or sign up for the 50-row free workflow with CSV/XLSX and export.