How to use Remove CSV Duplicates
Remove repeated rows using selected key columns.
- Choose a CSV. Select a key column or match the entire row, choose whether to ignore case and outer whitespace, and keep the first or last occurrence.
- Process the selected files, then inspect the preview, dimensions or warnings.
- Download a new copy and check it before replacing or sharing the original.
How processing works
Rows are compared using either all columns or one chosen key. Optional case folding and outer-whitespace trimming affect comparison. The first or last occurrence is kept according to your selection.
A quick example
Match on Email to remove repeated entries while retaining the most recent row.
Assumptions, edge cases & limits
- A single-key match can discard rows whose other fields differ.
- The default comparison ignores case and trims outer whitespace; change these settings if differences matter.
- Matching is exact under the selected options, not fuzzy matching. Check the removed-row export.
Questions about Remove CSV Duplicates
Can I remove CSV duplicates by email while keeping the latest row?
Choose the email column and Keep Last, with rows ordered oldest to newest. This keeps the last matching row in file order; it does not inspect a timestamp or determine which record is actually newest.
Does trimming for comparison rewrite the retained data?
No. Trimming and case folding are used to compare keys. Review the kept and removed outputs to confirm the selected matching rule represents your data.
Are my files or inputs uploaded?
Calculation and file processing run in your browser without a processing upload. Downloads go to your device. Choosing a next-step transfer creates a temporary local copy for that workflow. Region preferences are stored separately from tool inputs. See our privacy details.
Can I use this tool for free?
Yes. No signup, subscription or payment is required to use the tool or download its output. File tools have device and size limits; a smaller batch may work better on a phone.
A result or explanation needs correcting? Tell us the tool name and an example.