Email Deduplicator — Remove Duplicate Emails Instantly
Duplicates creep in from merged spreadsheets, repeated form submissions and CRM exports. Email Deduplicator collapses them — optionally merging Gmail's dot-trick and googlemail.com variants so alice.smith+news@gmail.com and alicesmith@gmail.com become one entry.
- 100% in your browser
- No signup · no uploads
- Free to use
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Results
Nothing processed yet. Add content above and press the action button — everything runs locally in this tab.
History
Optionally remember runs on this device, sealed with your passphrase. Off by default; entries expire after 30 days.
Expires after 30 days; forgetting the passphrase erases access permanently.
How it works
- 01
Add your content
Paste text or drop TXT, CSV, XLSX, DOCX and PDF files into the workspace.
- 02
Run the tool
One press runs the pipeline locally in a Web Worker. Change the options and results update automatically.
- 03
Copy or download
Export results as TXT, CSV or JSON. Your content is never uploaded.
Where duplicates come from
Merged spreadsheet exports, repeated form submissions, CRM syncs that create a new row instead of updating, case drift between systems (Jane.Smith@Gmail.com vs jane.smith@gmail.com), and Gmail's own aliasing where dots and plus-tags produce superficially different strings for the same inbox. A list that reads as 5,000 subscribers is routinely 4,200 people once these collapse.
Duplicates cost real money: double sends annoy recipients, inflate per-contact billing in mail platforms, skew open-rate denominators, and trigger spam complaints from people who unsubscribed one copy but kept receiving the other. Dedupe before every send, not just during spring cleaning.
Three merge levels, from safe to smart
Exact matching collapses byte-identical entries. Case-insensitive matching additionally folds Alice@Example.COM into alice@example.com — safe everywhere, because mail systems treat domains case-insensitively and local parts effectively so in practice. Gmail smart merge goes further: dots in the local part are ignored, googlemail.com equals gmail.com, and plus-tags fold into the base address, so a.l.i.c.e+news@googlemail.com and alicesmith@gmail.com become one entry.
Use the first two levels unconditionally. Enable Gmail merging when the variants provably reach the same inbox — newsletters, product updates, transactional mail. Disable plus-tag folding when tags carry segmentation meaning, such as per-campaign tagged signups you intend to analyze separately.
- Exact → always safe, zero judgment calls
- Case-insensitive → safe; keeps first-seen order and casing
- Gmail smart merge → powerful; only for true same-inbox aliases
What never to auto-merge
Different domains are different people — alice@yahoo.com and alice@gmail.com must never collapse. Dots matter on non-Gmail providers; Outlook, Yahoo and corporate servers treat them as significant characters. Near-miss typos (gmial.com vs gmail.com) look like duplicates to humans but are distinct deliverability fates; fix those with validation, not merging.
The workspace preserves first-seen order through dedupe so signup chronology survives, and reports how many entries collapsed. Keep that removed-addresses count as an audit trail, then sort afterward if alphabetical output is needed.
Dedupe cadence that sticks
Dedupe at intake (every import), before every send (lists drift between sends), and after every merge (two clean lists make a dirty union). Pair with the Counter to track duplicate rate over time — a rising rate points at a broken form or a double-firing sync, and fixing the source beats re-deduping forever.
Last reviewed: 2026-09-06 · By the Email Extractor Team · About our privacy-first approach
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Frequently asked questions
How does Gmail dot-trick merging work?
Gmail ignores dots in the local part and treats googlemail.com identically to gmail.com. With smart merging on, a.l.i.c.e@gmail.com, alicesmith@googlemail.com style variants collapse to a single canonical address.
Are plus-tags treated as duplicates too?
By default yes: alice+news@gmail.com merges into its base address. Disable plus-tag normalization if those aliases carry meaning for your segmentation.
What order is the result in?
First-seen order — the first occurrence keeps its position, so your original ordering survives deduplication. Use the Sorter afterwards if you need alphabetical order.