How to remove duplicate rows from a CSV or Excel file
Clean customer lists and exports by removing duplicates across the whole row or by a column such as email, ignoring differences in capital letters.
Updated 2 October 2026
Duplicate rows creep into customer lists, mailing lists and exports whenever data is combined from different places. Sending the same email twice or counting a customer twice is easy to avoid.
Decide what counts as a duplicate
- Whole row: rows that are identical in every column.
- By key columns: rows with the same value in chosen columns, such as email, or first name, last name. This catches the same customer entered twice with a different phone number.
How to remove them
- Open Remove duplicates and choose your CSV or Excel file.
- Leave columns empty for whole-row duplicates, or type the column names to compare on.
- Keep "Ignore upper/lower case" ticked so Ali@Example.com and ali@example.com match.
- Download; the file name tells you how many rows were removed. The first occurrence of each row is kept.
Clean first for better matches
Extra spaces make identical values look different. Run Clean CSV / Excel with "Trim extra spaces" first, then remove duplicates.
Combining several lists?
Use Merge CSV / Excel to put them in one file, then remove duplicates across all of them in one go.