JSON & tables / Clean-up
Data Deduplicator: Remove Duplicate Rows by Column
Paste CSV data or a list and remove duplicate rows, comparing by the columns you choose or the whole row, optionally ignoring case and extra spaces, keeping the first or last copy, and see which values repeated and how often.
Data Deduplicator: Remove Duplicate Rows by Column: Each row gets a key from the chosen columns, tidied as asked, and only the first (or last) row with each key is kept, in the original order. In the sample, comparing by email and ignoring case keeps Ana and Ben and removes the second Ana and Cy, whose email repeats Ben's. Runs 100% locally in your browser with zero server file uploads.
- Category
- Developer tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
Result
name,email Ana,ana@example.com Ben,ben@example.com
| Repeated value | Times |
|---|---|
| ana@example.com | 2 |
| ben@example.com | 2 |
Rows count as duplicates when the ticked columns match, or the whole row if none are ticked. Ignoring case and extra spaces catches entries like “ANA ” and “ana”. The result keeps the original order and can be pasted back into a spreadsheet. Quoted CSV fields with commas or line breaks are handled.
Matching near-duplicates
Ignoring case and spaces catches “ANA ” and “ana”; spelling differences and nicknames still need a human eye or a fuzzy-matching tool.
Plain lists
For a simple list with no columns, remove duplicate lines is quicker.
How to use it
- Paste CSV data, with or without a header row.
- Tick the columns to compare, and choose case, spaces, and which copy to keep.
- Copy the de-duplicated CSV.
Privacy & limitations
Your data stays in your browser and is never uploaded.
Related tools
Frequently asked questions
How is this different from removing duplicate lines?
It understands columns: two rows can be duplicates by email even when the names differ, and quoted commas inside cells are handled.
Which copy should I keep?
The first copy for the earliest record; the last for the most recent update, when rows are in date order.
Can it handle large files?
Tens of thousands of rows work in the browser; for millions, a database or a command-line tool is better.
Free tool · runs in your browser · no account required