Method 1: Excel's built-in Remove Duplicates
- Select your data range (or a single cell inside it).
- Go to the Data tab → Remove Duplicates.
- Tick the columns that define a duplicate and press OK. Excel reports how many rows were removed; the first occurrence of each duplicate is kept.
Limitations: matching is exact (an extra space or different capitalization means "not a duplicate"), it modifies the sheet in place, and it needs Excel.
Method 2: the tool on this page
Use it when you want case-insensitive matching, a contact-list workflow, a non-destructive cleaned copy, or you simply don't have Excel handy. It reads .xlsx, .csv, and .tsv up to ~50,000 rows, entirely offline in the browser. Still on the pre-2007 binary format? Those load too: see removing duplicates from an .xls file for what changes with legacy workbooks.
For huge files or automation
The Dedupe API accepts CSV up to 2 MB on the free tier and returns the cleaned file, which is useful in scripts and pipelines.
FAQ
Frequently asked questions
Does Excel have a built-in way to remove duplicates?
Yes. Select your range, then Data → Remove Duplicates. It removes exact matches on the columns you tick and keeps the first occurrence. Use the tool on this page when you need case-insensitive matching, don't have Excel open, or don't want to modify the original file.
Which row does Excel keep?
Both Excel's built-in feature and this tool keep the first occurrence and delete later ones, preserving row order.
Can I remove duplicates based on one column only?
Yes. Click the column chips above so only that column is highlighted. Rows are then considered duplicates when that column matches, regardless of other columns.
Will my spreadsheet be uploaded?
No. The file is parsed by JavaScript in your browser; nothing is transmitted. You can watch the Network tab in your browser's developer tools to verify.
Does it handle .xlsx and .csv?
Both, plus .tsv. The cleaned result downloads as CSV, which Excel opens directly.
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