About this tool
What does it normalize?
Email addresses into canonical form for dedupe and login matching: lowercasing, trimming, Gmail dot/plus-tag rules (optional), and internationalized-domain handling — so the same mailbox always matches itself.
How to use it
- Paste addresses, singly or as a list.
- Choose provider rules (Gmail dots, plus addressing).
- Copy normalized output for imports and comparisons.
Examples
- Deduplicating
John.Doe@gmail.comvsjohndoe@gmail.com. - Login matching that survives
+tagaliases. - Cleaning a 10k-row newsletter list before sending.
Important limitations
- Plus/dot rules are Gmail-specific — other providers treat dots as significant.
- Normalization aids matching; it never verifies a mailbox exists.
- Case sensitivity is technically allowed by RFC — lowercase by convention, with rare exceptions.
Privacy
Local string processing. Address lists are sensitive personal data — they never leave your browser here.
Frequently asked questions
Are dots irrelevant in Gmail?
Yes, Gmail ignores them — most other providers do not.
What about +tags?
Gmail delivers to the base address; great for filtering, bad as a security boundary.
International domains?
Converted to punycode for transport; display form preserved.