Email Normalizer & Deduplicator

Email addresses

Normalization options

Lowercase all emails Remove duplicates Remove Gmail dots (john.doe → johndoe) Remove Gmail plus aliases (user+tag → user) Validate format (remove invalid emails)

What is email normalization?

Email normalization is the process of standardizing email addresses to a canonical form — converting to lowercase, removing whitespace, and applying provider-specific rules like Gmail's dot and plus alias removal.

Gmail & provider rules

Gmail treats dots in the local part as insignificant: j.doe@gmail.com and jdoe@gmail.com are the same inbox. Plus aliases (user+tag@gmail.com) are also stripped. This tool handles both rules automatically.

Privacy first

All processing happens entirely in your browser. Your email list never leaves your device — no server, no upload, no log.

Frequently asked questions about Email Normalization

Everything about cleaning and deduplicating email lists

Email normalization converts email addresses to a consistent, canonical form. This includes lowercasing, trimming whitespace, and applying provider-specific rules. Normalized lists have fewer false duplicates and improve deliverability for email campaigns.

Gmail ignores dots in the local part of the address. This means j.o.h.n@gmail.com, john@gmail.com, and j.o.h.n@gmail.com all deliver to the same inbox. This tool removes all dots from Gmail addresses so these variations are correctly treated as duplicates.

Gmail allows you to add a plus sign and any text after your username: user+newsletter@gmail.com still goes to user@gmail.com. These aliases are useful for filtering, but can create duplicates in mailing lists. This tool strips everything after the plus sign for Gmail addresses.

Duplicate emails in your mailing list waste money (most ESPs charge per email sent), hurt engagement metrics, and may result in complaints or unsubscribes. Normalization before deduplication catches duplicates that differ only in case or Gmail-specific variations.

Normalize and deduplicate email lists

The email normalizer cleans lists of email addresses: it unifies the spelling, recognizes variants of the same address and removes duplicates. With Gmail in particular, dots and plus aliases mean the same person can appear several times in a list. The tool is for anyone who wants to keep newsletter, CRM or contact lists clean, and it works entirely in the browser.

Common use cases

Clean newsletter lists: Remove duplicate sign-ups before you send a campaign, saving costs and delivery problems.
Detect Gmail variants: Treat "john.doe@gmail.com" and "johndoe+news@gmail.com" as the same address.
Prepare data imports: Normalize addresses before importing them into a CRM or mailing system.
Check data quality: Unify upper- and lowercase and strip spaces to get consistent records.

How to clean your list

1 Paste your list of email addresses into the input field.
2 Choose the rules you want, such as resolving Gmail aliases.
3 The tool normalizes the addresses and flags duplicates.
4 Copy the cleaned, unique list or download it.

Clean lists, better delivery

Duplicate or inconsistent addresses cost real money with email services and hurt deliverability when the same person is contacted several times. Normalization creates a single clean basis – note that alias rules differ by provider: what applies to Gmail does not necessarily apply to other domains. Because processing happens locally, these often personal addresses never leave your device.

Free tools that pair well with this one – right in your browser, no sign-up.

Favicon Generator Generate favicons from images QR Code Generator Generate QR codes for URLs, WiFi & more OG Meta Generator Generate Open Graph & Twitter tags SVG Placeholder Create custom placeholder images