Email Address Normalizer
Normalize email domains while preserving local-part case and tags by default. Optionally apply personal Gmail rules and deduplicate exact normalized addresses.
Preserve mailbox identity by default
Enter one bare mailbox address per line. The domain is lowercased and internationalized domain names are converted to ASCII. The local part keeps its case, dots and plus tags by default: User@example.com and user@example.com are not automatically merged. Unicode local parts are not normalized into a presumed equivalent form.
Report mode preserves each input row, its normalized address, whether it changed, any earlier duplicate row and invalid-address results. Address-list mode produces a copyable list but rejects the operation if any row is invalid, avoiding a silently incomplete export. Deduplication compares the exact normalized result and preserves first occurrence order.
Provider rules require an explicit choice
The optional Gmail rule applies only to personal gmail.com addresses. It lowercases that local part, removes its dots and removes the +tag suffix. It does not alter Google Workspace custom domains or apply Gmail behavior to other providers. The googlemail.com alias is not automatically rewritten.
Quoted local parts are parsed and re-quoted when needed; display names, comments and domain literals are outside this input format. Limits are 1,000 rows, 200,000 total characters, 64 UTF-8 bytes in the local part and 254 bytes in the normalized address. This checks syntax and transforms text, not MX records, delivery, ownership or account equivalence at an unknown provider.
Reference
Questions & answers
Why are plus tags preserved on other domains?
Providers can use different mailbox rules. Removing a suffix without knowing those rules can merge distinct accounts or change the destination.
Does a valid result mean email delivery will work?
No. Syntax and normalization do not prove that a domain accepts mail or that a mailbox exists.
Is my input uploaded?
No. Parsing and generation run in your browser. Engines and datasets load from this site; the tool does not store input or send it to a processing API.