Email address normalizer
Two addresses can look different and reach the same person. Normalising them is how you stop counting one customer twice, and how you stop somebody claiming a second free trial with a dot moved.
Free, no signup, no daily limit. We do not store what you check here.
What is safe to normalise and what is not
Case in the domain is always insignificant. Case in the local part is technically significant and universally ignored in practice, so lowercasing is safe. Plus tags are safe to strip for comparison at every provider that supports them. Dots are the dangerous one: they are insignificant at Gmail and significant almost everywhere else, so collapsing them globally merges addresses belonging to different people. This tool only collapses them where the provider says they do not matter.
Normalise for comparison, send to the original
The canonical form is for deduplicating and for checking whether somebody already has an account. It is not the address to send to. A plus tag often carries routing or filtering the recipient set up deliberately, and stripping it before sending can drop the message into a folder nobody reads — or make an unsubscribe link fail to match.
Questions
Should I store the normalised address or the original?
Both. Store the original to send to, and the canonical form in a separate indexed column to compare against. Storing only the canonical form loses information you cannot reconstruct.
Does this stop free-trial abuse?
It stops the laziest version of it. Somebody determined will use a different provider or a disposable domain, which is a different check — but plus tags and Gmail dots are what most casual repeat signups actually use.
Related tools
Email list deduplicator
Paste a list and find the duplicates plain matching misses — plus tags, Gmail dots, provider aliases and case. Free, runs on your input only.
Disposable email address checker
Check whether an email address uses a throwaway or temporary inbox provider. Free, no signup.
Free email address validator
Check syntax, DNS, MX records and deliverability signals for any email address. Free, no signup.
When you need more than a free tool
This page answers what can be determined offline and from public DNS. The API adds live carrier and mailbox verification, a calibrated confidence score, and the full evidence trail behind every verdict.
Credits never expire. Inconclusive verdicts are never billed. Cancel in one call. See pricing or read the docs.