Remove duplicate contacts from a CSV — without uploading your list
Years of exports, imports and merged accounts leave every contact list full of duplicates. Here's a three-step clean-up — export, dedupe in your browser, import back — with nothing uploaded and no automatic merging.
The three-step workflow
- Export your contacts as CSV. Gmail: Google Contacts → Export → Google CSV. Outlook: People → Manage → Export contacts. Google Sheets or any spreadsheet: File → Download → CSV.
- Clean it here. Open the free contact cleaner and drop the file in (or paste the CSV straight in). Exact duplicates are removed; fuzzy matches — typos, nicknames, formatting differences — are flagged as possible, and you decide each one.
- Import the clean file back. Delete the old list in your contacts app and import the cleaned CSV. Done until next year's mess.
What counts as a duplicate
Exact duplicates are rows that match after normalisation: emails compared case-insensitively, phone numbers compared with formatting stripped. Those are safe to remove and the tool removes them automatically.
Possible duplicates are the interesting ones: j.smith@ vs j.smith1@, "Anna" vs "AnnA ", two entries that share an email but differ in a name typo. The tool flags them with a similarity score — it never merges anyone by itself. You review each pair and decide.
Why not just Excel's "Remove Duplicates"?
Excel only removes rows that are completely identical — same name, same email, same everything. Real-world duplicates almost never are: one has a phone number filled in, the other a nickname. That's exactly why Excel's button feels useless on a real export. This tool compares the fields that matter (email, phone, name) instead of the whole row.
A privacy note worth reading
A contacts export is one of the most personal files you have — names, emails, phone numbers, sometimes addresses and birthdays. Think twice before uploading one to a random free "dedupe contacts" website. This cleaner runs entirely in your browser: your list never leaves your device, and you can verify that by going offline and deduping anyway.
contacts_export.csv — 1,284 rows checked locally:
412 exact duplicates 37 possible matches
possible = you review each one before merging
✓ clean CSV saved — never uploaded, 0 bytes sent
What a dedupe pass looks like (illustration — demo rows, never real data):
Like the tool? Own it.
The free page processes 3 CSVs a day. The €9 Contact List Cleaner download is the same tool as a single file: no daily limit, offline forever — for every future export. One-time payment, no subscription.
Get Contact List Cleaner — €9 once
Questions people ask
Will it merge two different people by mistake?
It never merges anyone automatically — that's the core safeguard. Fuzzy matches are flagged as "possible" and you review every single merge before anything changes.
Which formats does it accept?
CSV — the export format of Gmail, Outlook and Google Sheets. Paste it in or choose the file; the first row is treated as column headers.
Does my contact list get uploaded anywhere?
No. The dedupe runs inside the page — no server, no account, no network calls. Wi-Fi off? Still works.
How big a list can it handle?
Thousands of rows are fine — it runs on your machine, so the ceiling is your browser's memory, not a server's patience. The free page's cap is 3 imports a day.
More step-by-step guides
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