Why Gmail addresses with dots are duplicates
Google ignores periods in the local part of a Gmail address. john.smith@gmail.com, johnsmith@gmail.com and j.o.h.n.s.m.i.t.h@gmail.com all deliver to the same mailbox, and Google treats them as one account for sign-in.
That means most “unique” counts are inflated. If you dedupe on the raw string, you send the same person two or three emails under slightly different addresses — and the second one is the one they mark as spam.
Where the dot rule applies
- Gmail only —
gmail.comand its aliasgooglemail.com. - Not Google Workspace. A custom domain hosted by Google (
@yourcompany.com) treats dots as significant;j.smith@yourcompany.comcan be a different person fromjsmith@yourcompany.com. - Not other providers. Outlook, Yahoo and Fastmail all treat dots as meaningful. Applying Gmail's rule globally will merge two real people and silently delete one of them.
The plus tag is the bigger problem
ana+newsletter@gmail.com is not a separate subscriber. Anything after + is an internal label — the same trick works on Outlook and many corporate domains too. Lists assembled from signup forms are full of these, because people add a tag to see who sold their address.
Both normalisations belong in the same pass. Dedupe on the canonical form — lowercase, no plus tag, dots collapsed for Gmail only — and you keep the most recent row rather than the first one you saw.
What to do with the rows you merge
Keep the earliest signup date and the most recent activity, not strictly the newest row. If you simply keep the last one, you can lose the original opt-in timestamp — which is exactly the evidence you need if someone claims they never subscribed.
Check your own list in about 30 seconds. Paste or drop a CSV — duplicates, typos, role addresses and dead domains, all handled in your browser. Free for the first 100 addresses, $19 once for unlimited.
Open the toolCommon questions
Is it legal to merge Gmail dot variants into one contact?
Yes — you are removing a duplicate record for one person, not creating a new one. Keep the earliest consent date so your opt-in record stays intact.
Do dots matter in the domain?
No, domain names are always case- and dot-insensitive in the sense that the domain itself is fixed; you cannot add dots to gmail.com and reach a different server.
Last updated 2026-10-23.