Comma Separator

How to use it

1. Paste your list into the left box. One item per line is the usual starting point, but you can also paste a comma, semicolon, space or tab separated list and tell the tool which one to split on.
2. Pick a quick-start button, or set the delimiter yourself under Join with.
3. Tick Remove duplicates if you want one of each, or switch Show to see only the repeats.
4. Press Copy. The result is already on your clipboard.

The order things happen in

Results are never surprising if you know the order of operations. The tool always works through the same sequence, whatever combination of options you pick:

1. Split the pasted text into items.
2. Trim the spaces around each item, if that box is ticked.
3. Skip blanks, so empty lines never become empty entries.
4. Handle duplicates — remove them, or keep only the repeats, or keep only the one-offs.
5. Sort, if you asked for a sort.
6. Change case, if you asked for that.
7. Quote and wrap each item with your prefix and suffix.
8. Join everything with your delimiter and wrap the whole result.

Because case is changed after duplicates are handled, turning on UPPERCASE will not silently merge two entries. If you want Apple and apple treated as the same thing, use Ignore case when matching instead — it keeps the first spelling it saw.

What people use it for

Building a SQL IN clause

Copy a column of IDs out of a spreadsheet, hit SQL IN (…), and you get IN ('101', '102', '103') with the duplicates already gone. This is the single most common reason people reach for a tool like this.

Cleaning a mailing or tag list

Lists that have been copied between documents collect blank lines, stray spaces and repeats. Splitting on new lines with Remove duplicates turned on gives you a clean list, and the counter tells you exactly how many repeats there were.

Finding what got entered twice

Sometimes the duplicates are the point — a double-booked reference, a barcode scanned twice, an email address that appears in two exports. Setting Show to Only items that repeat lists each repeated value once, so you can see what went wrong rather than just quietly deleting it. Only items appearing once does the opposite, which is useful for comparing two lists pasted together.

Turning a column into a code array

Add double quotes, join with a comma and a space, then wrap the output in [ and ] to paste a list straight into JavaScript, Python or JSON.

Notes on the details

• Line endings. Windows, Mac and Unix line breaks are all recognised, so pasting from any editor works.
• Escape sequences. In the custom split and join boxes, typing \n means a new line and \t means a tab.
• Quotes are not escaped. If an item already contains a double quote and you wrap it in double quotes, the result will contain both. That is deliberate — this is a list formatter, not a CSV encoder.
• Sorting numbers. Plain A-to-Z sorting puts 100 before 9. Choose Smallest number first to sort numerically; anything that is not a number is listed after the numbers.
• Your options are remembered in this browser only, so the tool opens the way you left it. Clearing site data resets it.

Questions

Is there a limit on how much I can paste?

There is no limit imposed by us. The work happens on your own machine, so the real limit is your device's memory. Lists of tens of thousands of lines are handled without trouble.

Does my list get uploaded anywhere?

No. The tool is a JavaScript function running in your browser. Nothing you paste leaves the page, which you can confirm in the Network tab of your browser's developer tools — or by disconnecting from the internet and watching it carry on working. See our Privacy Policy for the full position.

Which entry is kept when duplicates are removed?

The first one. Order is preserved, so the list keeps the sequence you pasted unless you choose a sort.

Can I split on one character and join with the same one?

Yes, and it is a useful way to tidy a list in place — splitting on commas and joining with a comma and a space normalises the spacing of a messy list without changing anything else.

What counts as a blank entry?

Anything that is empty or contains only spaces and tabs. Blank entries are skipped by default; untick Skip blank entries if you need to keep the positions, for example when the list lines up with another column.