Remove duplicate addresses from a mailing list, free
Upload an Excel or CSV file, review what was found, and download a clean list. Your file is processed in your browser and never uploaded.
What counts as a duplicate
Two rows count as the same address when the columns you choose match after tidying them up:
- Capital letters and punctuation are ignored: "JOHN SMITH" matches "John Smith".
- Common abbreviations match: Street/St, Avenue/Ave, Road/Rd, Apartment/Apt/#, North/N.
- State names match their codes: "Massachusetts" matches "MA".
The first row is kept and later copies are removed. The report lists every removed row so you can check them.
Other clean-ups
- Restore ZIP code leading zeros that Excel removes (2134 → 02134).
- Change state names to 2-letter codes.
- Fix names and addresses typed in ALL CAPS or all lowercase.
Why duplicates survive in a mailing list
Duplicates usually arrive when two lists are merged: last year's customers and this year's, a wedding list from two families, or a contacts export joined to a sign-up sheet. Excel's own Remove Duplicates only removes rows that match character for character, so "12 Oak St" and "12 Oak Street" both survive it.
Every duplicate costs a label, an envelope and a stamp, and on a wedding or fundraising list it also means somebody gets the same thing twice. It is worth the two minutes before you print.
Ready to print? Turn the clean list into labels.
Duplicate questions
How does it decide two addresses are the same?
It compares the columns you choose after ignoring capitals and punctuation, expanding common abbreviations such as Street and St or Apartment and Apt, and matching state names to their codes. So "12 Oak Street, Apt #3" and "12 oak st apt 3" are treated as one address.
Which copy is kept?
The first one in the file. Every removed row is listed in the report next to the row it matched, so you can check the result before downloading.
What do I get back?
A CSV with the same columns as your file, minus the duplicates, with any clean-ups you switched on applied.
Is the file uploaded anywhere?
No. It is read and cleaned in your browser, and the CSV you download is generated there too.