Expected duplicates are not shown
Extra spaces, different case, or punctuation can make two values look different to a strict comparison.
Normalize the source list first, or use the SKU or email cleaner when the values need domain-specific cleanup.
Use this tool
Prepare the input and run the tool
Paste one value per line. Result: Copy the duplicate report.
Ready.
Duplicate report appears here.
Data handling: Files and pasted data are processed in this browser session.
Tool guide
How to use Duplicate Finder
Use this when a list looks suspicious and you need the repeated values only. It is useful before imports, email sends, and inventory checks.
What this tool does
Paste a list and get the values that appear more than once.
- Input
- Paste one value per line
- Output
- Copy the duplicate report
Tool advantages
- Runs in this page; the file or pasted data is not sent to a new app.
- Keeps the preview, report, and download in the same screen.
- Gives you a report you can use as a cleanup list.
Step-by-step usage guide
- 1Paste the list.
- 2Run the duplicate check.
- 3Copy the repeated values and counts.
Common errors and fixes
The report includes blank lines
Copied spreadsheet ranges can include empty rows or hidden separators.
Remove blank rows before checking, then rerun the duplicate report.
Intentional repeated values are mixed with mistakes
Some lists allow repeated labels, while IDs, emails, and SKUs usually should be unique.
Filter the source to the identifier column you actually need to audit.
When to use Duplicate Finder
- You are checking files before an upload, import, share, or delivery.
- You want to confirm the result before sending it to another system.
- You need a copied result, downloaded file, or report that can be reviewed outside the page.
FAQ
Does this compare values case-sensitively?
Values are matched case-insensitively so repeated emails, SKUs, and IDs are easier to catch.
Does my list leave the browser?
The duplicate check runs in this page.