Excel Duplicate Finder & Remover
Find, highlight and remove duplicate rows in an Excel or CSV file. Everything runs in your browser, so your spreadsheet is never uploaded to a server.
This free tool finds and removes duplicate rows in an Excel spreadsheet or CSV file without leaving your browser. Drop in a .xlsx, .xls, or .csv file, choose which columns should decide what counts as a duplicate, and download a cleaned file, a file of just the duplicates, or a copy with every duplicate highlighted in color.
Unlike most online dedupe tools, nothing is uploaded. Customer lists, mailing lists, transaction exports, and any file with names, emails, or other personal data are processed entirely on your own device, which also means there is no row limit imposed by an upload cap.
How to find and remove duplicates in Excel online
- Add your spreadsheet
Drag an .xlsx, .xls, or .csv file into the box above, or click to browse. The first sheet is read locally in your browser.
- Pick the columns to match on
Choose which columns define a duplicate. Match on a single column like Email to catch repeats even when other cells differ, or several columns together for an exact match.
- Find the duplicates
Click "Find duplicates" to see how many duplicate rows and groups there are, with the matching rows highlighted in an on-page preview.
- Download the result
Download the file with duplicates removed, a file containing only the duplicates, or a highlighted .xlsx that colors every duplicate row so you can review them in Excel.
Match on one column or several
The columns you match on decide what counts as a duplicate, and that choice is the whole game:
- One key column: tick just Email (or an ID or invoice number) and two rows are treated as duplicates whenever that value repeats, even if the name, date, or amount differs. This is how you deduplicate a mailing list.
- Several columns together: tick First name and Last name and a row is a duplicate only when both match, so two different people who happen to share a first name are both kept.
- Every column: select all columns to remove only rows that are identical end to end.
Matching is not case sensitive by default, so "ABC" and "abc" are treated as the same value. Tick "Case sensitive" if you need them kept apart.
Highlight duplicates instead of deleting them
On important data it is safer to look before you delete. This tool highlights every duplicate row in an on-page preview the moment you click Find duplicates, so you can scan them first. When you want that review inside Excel itself, download the highlighted .xlsx: it is your original data with each duplicate row filled amber, exactly like Excel's own Highlight Duplicates formatting, so you can sort, filter, or delete them manually.
Prefer a clean file straight away? Download the version with duplicates removed instead. It keeps the first occurrence of each duplicate group and drops the rest, which is the same rule as Excel's built-in Remove Duplicates.
Want to do it inside Excel yourself instead? Our guide on how to remove duplicates in Excel walks through the Remove Duplicates button, the UNIQUE function, Conditional Formatting, and Power Query, plus why Excel sometimes misses duplicates.
Why use this converter?
Private by design
Conversion runs in your browser. Your files are never uploaded, stored, or seen by anyone.
Genuinely free
No daily task limits, premium tiers, or watermarks. Local conversion costs nothing to run.
Instant results
No upload and download queues. Files convert in about a second, even on slow connections.
Works everywhere
Windows, Mac, Linux, iPhone, Android: any modern browser, no app or software install.
Frequently asked questions
How do I find duplicates in an Excel file?
Drop your .xlsx, .xls, or .csv file into the tool above, choose the columns that define a duplicate, and click Find duplicates. The tool shows how many duplicate rows and groups it found and highlights the matching rows in a preview, all in your browser.
Is my spreadsheet uploaded to a server?
No. The file is read and processed locally in your browser using JavaScript. Your spreadsheet never leaves your device, which makes this safe for customer lists, mailing lists, and any file with personal or financial data.
How do I remove duplicates based on one column?
Select only that single column in the "Match on these columns" list before clicking Find duplicates. Two rows are then treated as duplicates whenever that one column matches, even if other columns differ, and the cleaned download keeps the first matching row.
Can I highlight duplicates instead of deleting them?
Yes. The on-page preview highlights every duplicate row automatically, and you can download a highlighted .xlsx that colors each duplicate row so you can review them in Excel before deciding what to remove.
Does it keep the first row when removing duplicates?
Yes. When it removes duplicates it keeps the first occurrence of each duplicate group and drops the later copies, matching how Excel’s built-in Remove Duplicates works. Sort your data first if you need a specific row kept.
What file formats does it support?
It reads Excel .xlsx and .xls files and .csv files, and produces .xlsx downloads. Only the first sheet of a workbook is processed.
Is there a row limit?
There is no fixed limit. Because nothing is uploaded, the practical limit is your device’s memory, and files with tens of thousands of rows work fine on a normal computer.