How to clean an email list
Paste values into Email addresses or load a TXT, CSV, or TSV file. The Email List Cleaner splits the input into entries, removes whitespace, applies the selected rules, keeps the first valid address for each comparison key, and puts later duplicates and malformed values in separate results.
- Paste addresses into Email addresses, or drop a TXT, CSV, or TSV file in the drop area and choose browse files. Separate entries with newlines, commas, semicolons, or tabs.
- Choose Casing, then select any needed options: Extract addresses from
Name <email>entries, Remove plus-tags ([email protected]), or Treat dots as insignificant for Gmail / Googlemail. - Read Clean list as the results update. Duplicates removed and Malformed - needs review appear when the input contains those records.
- Use Copy, Export TXT, or Export CSV beside Clean list. Each review table has its own Export CSV button.
How to remove duplicate email addresses
Choose Lowercase all addresses to lowercase the local part and domain in the output. Lowercase domain changes the domain only. Preserve original casing leaves the displayed casing in place. Duplicate comparison uses a lowercase key, so the first well-formed match stays in Clean list and later matches move to Duplicates removed.
[email protected]
[email protected]
[email protected][email protected]
[email protected]The second [email protected] appears with its original entry and the normalized address already kept. The tool checks the normalized value before comparing duplicate keys, so malformed values go to Malformed - needs review.
How to normalize an email list
Enable Extract addresses from Name <email> entries for values such as Jane Doe <[email protected]>. Remove plus-tags changes [email protected] to [email protected] before matching. Treat dots as insignificant for Gmail / Googlemail removes dots from the local part for those domains before matching.
The tool removes whitespace throughout each entry, and blank entries are ignored. The format check rejects values longer than 254 characters, local parts longer than 64 characters, addresses without exactly one @, domains without a dot, malformed domains, and values outside the accepted email pattern.
How to review the cleanup results
Clean list contains the first normalized version of each valid comparison key. Duplicates removed shows each later original entry beside the normalized address that was kept.
Malformed - needs review shows the original value and a short reason, such as Missing @ symbol., Multiple @ symbols., or Domain has no dot. Check those rows before exporting a clean list.
When several labels should compare as one address, select Remove plus-tags or Treat dots as insignificant for Gmail / Googlemail. Export the resulting clean list as TXT or CSV.
Choose the right dataset cleaning tool
Email List Cleaner handles address normalization, duplicate separation, malformed-entry reasons, and clean-list exports. Dataset Clean Tools covers other dataset cleanup jobs.
Use Phone Number List Cleaner for phone lists with country rules, prefixes, extensions, or E.164 and national output. Choose Data Cleaner for CSV, TSV, Excel, JSON, JSONL, XML, or YAML input that needs format-aware cleanup. Choose Remove Duplicate Rows when records should match by full row or selected key columns.
What the format check confirms
The check covers address shape. It does not perform DNS or MX lookups, test deliverability, or confirm that a mailbox exists. The page reads and processes the supplied list in the browser, then creates the exports locally; its cleaning code makes no network request for that list.
Frequently Asked Questions
How do I clean an email list and remove duplicates?
Paste the list or load a TXT, CSV, or TSV file, then review Clean list and Duplicates removed. The first well-formed address for each lowercase comparison key stays in Clean list.
How do I normalize email addresses before exporting?
Set Casing and select the rules you need, such as Remove plus-tags or Treat dots as insignificant for Gmail / Googlemail. Clean list reflects those rules and can be copied or exported.
What does the Email List Cleaner mark as malformed?
It marks non-empty values that fail the email format check, such as entries with a missing or multiple @ symbols, a missing dotted domain, excessive length, or invalid characters. Each appears in Malformed - needs review with a reason.
Does the email list stay in my browser?
Yes. The page reads pasted text or the selected file in the browser, processes it there, and creates the exports locally. The cleaning code makes no network request for the supplied list.