CSV Contact List Cleaner

Normalize names, phone numbers & emails, and remove duplicate contacts from any CSV file — entirely in your browser. No data is ever uploaded.

Step 1 — Load your CSV

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Drop a CSV file here or click to browse
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How it works

  1. Load your CSV — drop a file or paste text. PapaParse auto-detects delimiters (comma, semicolon, tab) and encoding.
  2. Map columns — tell the tool which column is the name, phone, and email. You can skip any column you don't have.
  3. Clean automatically — full-width character conversion, whitespace stripping, phone normalization, email lowercasing, and empty-row removal all happen locally in your browser.
  4. Deduplicate — keep the first occurrence of any email address or phone number. Duplicates are counted and removed.
  5. Download — get a cleaned CSV ready to import into any CRM, mailing tool, or spreadsheet.

Frequently asked questions

Is my data safe? Does this tool upload my contacts to a server?
No data ever leaves your browser. All processing uses JavaScript running locally on your device. The file is read with the browser's built-in FileReader API, and the cleaned CSV is generated client-side with PapaParse. You can verify this by turning off Wi-Fi before using the tool — it works just the same.
What counts as a duplicate contact?
You choose the deduplication key: email address, phone number, or either (email OR phone). When two rows share the same normalized email or phone, the first occurrence is kept and subsequent ones are removed. Normalization is applied before comparison, so John@EXAMPLE.COM and john@example.com are treated as the same email, and 555-123-4567 and 5551234567 count as the same phone number.
How are phone numbers normalized?
By default, all non-digit characters — hyphens, parentheses, spaces, dots — are stripped, leaving only digits. For example, (555) 123-4567 becomes 5551234567. If you enable the E.164 option, a + is prepended to any number with 10 or more digits, producing +5551234567. This tool does not add country codes automatically — if your data already includes country codes, they will be preserved.
What does "full-width to half-width" conversion do?
Many East Asian input methods produce full-width characters — for example, Ａ (Unicode U+FF21) instead of A (U+0041), or ０ instead of 0. This option converts the entire Unicode full-width Latin and digit range (U+FF01–U+FF5E) to standard ASCII, making names and numbers consistent and searchable in any system.
Can I clean a CSV that has only phone numbers and no emails (or vice versa)?
Yes. Set unmapped columns to "— skip —" and choose the appropriate deduplication key. The tool processes only the columns you have mapped and skips everything else. You can also choose "Don't remove duplicates" if you only want normalization.
What CSV formats and delimiters does this tool support?
PapaParse auto-detects commas, semicolons, and tabs, and handles quoted fields containing commas or line breaks. Standard exports from Excel, Google Sheets, Salesforce, HubSpot, Mailchimp, and most CRMs are supported. The output file always uses comma separation with proper quoting, compatible with all major tools.