Find Duplicate List Items
Print all repeating items of a list. Runs entirely in your browser, so your data never leaves your device.
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Output
The result appears here as you type.
How to use Find Duplicate List Items
- 1. Paste your list. Add your list to the input pane, one item per line. This works with names, order IDs, email addresses or any other column of repeated values.
- 2. Decide whether to show counts. Enable Show how many times each item appears to see a count next to every repeated value. Leave it off if you only care which items repeat, not how often.
- 3. Review the repeated items. The output lists every item that shows up more than once. Use it to spot data entry mistakes or intentional repeats before you act on the list.
When to use Find Duplicate List Items
Find Duplicate List Items surfaces the values that occur more than once inside a list. It answers a different question than a dedupe tool: instead of removing repeats, it tells you exactly which ones exist and how badly.
- Catching double-entered customer records. A CRM export has customer emails pasted in twice by accident during a data migration. Running the list through this tool immediately shows which addresses were entered more than once.
- Spotting repeated SKUs in an inventory sheet. A warehouse spreadsheet lists product SKUs per shipment, and you suspect some were logged twice. The tool prints only the SKUs that appear more than once so you can investigate those rows.
- Verifying a raffle or giveaway entry list. Contest entries were collected from a form and some participants may have submitted multiple times. Finding the duplicates before drawing a winner keeps the giveaway fair.
- Checking counts with the frequency option. Turning on the counter shows exactly how many times each duplicate appears, which is handy when you need to know if someone entered a contest three times instead of just twice.
Examples
Find items that appear more than once
Input
apple banana apple cherry banana
Output
apple banana
About the Find Duplicate List Items tool
Find Duplicate List Items runs as plain JavaScript in your browser tab, with no server behind it. Print all repeating items of a list. Whatever you put in stays on your device from start to finish.
The tool is part of EditSafely's List Tools section, 114 single-purpose utilities built around the same idea: open the page, get the result, keep your data to yourself.
You can shape the output with the Show how many times each item appears setting, and the result refreshes the moment you change it. A worked example further down the page shows exactly what the tool produces for a real input.
That local-first design has practical benefits beyond privacy. The tool keeps working on a flaky connection once the page has loaded, results are instant because nothing round-trips to a server, and it is safe to use with confidential material.
Frequently asked questions
Does Find Duplicate List Items cost anything?
Yes, it is completely free. All 2,658 tools on EditSafely work without an account, a subscription or usage limits.
Is it safe to paste sensitive or confidential data?
No data leaves your device. The whole tool is JavaScript that runs inside your browser tab, so there is no upload, no server-side processing and no log of what you did. If you disconnect from the internet after the page loads, it keeps working.
How much text can I process at once?
There is no fixed limit. Because the work happens on your own device rather than on a shared server, the practical ceiling is your machine's memory, which comfortably handles inputs far larger than typical online tools allow.
Do I need to sign up or install anything?
Nothing to install and no account needed. Open the page in any up-to-date browser, including on a phone or tablet, and the tool is ready.
How do I use the result?
The output panel has a one-click copy button, and you can keep refining the input while you work; the result updates in place as you type.