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List to Comma Separated Converter

Text

Turns one item per line into a single delimited string.

Format presets

Paste one item per line — straight out of a spreadsheet column.
0 characters0 items read0 B out

Delimiter

Wraps every item — needed for SQL and JSON.
Only used when a quote character is set.
Turns a join into an array.
Break the output after N characters. 0 keeps one line.

Space after delimiter

Trim whitespace

Remove empty items

Remove duplicates

Duplicate match is case-sensitive

Applied after duplicates are removed.
Applied before the prefix and suffix.
Added before each item, inside the quotes.
Added after each item, inside the quotes.
Decimal places in the numeric summary.

Nothing to convert yet

Paste a list above, drop a .txt or .csv file onto the box, or load the sample to see trimming, deduping and sorting at once.

About This Tool

List to Comma Separated Converter – Turn Lines Into a Delimited String

Copying a column out of a spreadsheet gives you a vertical list, one value per line. Almost nothing else wants it that way. A SQL IN clause wants ('a', 'b'), a JSON array wants ["a", "b"], a CSV field wants a,b, and a config value might want a|b. This list to comma separated converter does that join, and reverses it just as easily when you need to split a delimited string back into one item per line for bulk editing.

How the conversion works

In the default direction your text is split on every line terminator — CRLF, LF, or a bare CR — so each line becomes one item. Those items then run through a fixed pipeline: trim whitespace, drop blank items, remove duplicates, sort, change case, add the prefix and suffix, and finally wrap each item in the quote character. Whatever survives is joined with your chosen delimiter and optionally wrapped in brackets. The order matters: because deduplication runs before the case change, turning off case-sensitive matching keeps the casing of the first occurrence rather than the last.

Reverse the direction and the same cleaning pipeline runs, only the input is split on a delimiter first. Auto-detect counts commas, semicolons, pipes, and tabs that sit outside quoted regions and picks whichever is most frequent, breaking ties in that order. Line breaks always end an item too, so a multi-row delimited file still comes out one value per line.

Building SQL IN lists and JSON arrays

The preset cards set the quote, delimiter, and bracket controls together. SQL IN list produces ('101', '102', '103') and JSON array produces ["101", "102", "103"]. Both are shortcuts, so you can adjust any single control afterwards — switch the quote to None, for instance, when your JSON array should hold real numbers rather than strings.

Quoting and escaping rules

A delimiter that also appears inside your data is the classic way to corrupt a list. Joining apple,pie and cherry with a comma gives apple,pie, cherry, which every parser reads back as three items. The fix is a quote character, and the tool warns you whenever this situation arises.

Quotes already inside an item need escaping, and the correct escape depends on who is reading the output. Doubling is the CSV convention — a " becomes "" — and is what spreadsheets expect. Backslash escaping writes \" instead, which is what JSON and most programming languages expect. Choosing the wrong one produces output that looks right and fails at parse time.

Trailing delimiters break parsers
A stray separator at the end of a list creates a phantom empty final item, which surfaces as an empty row, a null, or a syntax error. Leaving Remove empty items switched on prevents a blank line at the end of your paste from producing one.

Cleaning a messy paste

Real exports arrive with padded cells, blank rows, and repeats. Turning on trim, blank removal, and duplicate removal, then sorting A→Z, collapses " Beta / alpha / Beta / (blank) / ALPHA" into alpha, beta in a single pass. The statistics panel reports exactly how many blanks and duplicates were dropped, and the badge expands to show which values went. If every remaining item parses as a number, a numeric summary appears with the count, sum, minimum, maximum, and mean — a quick sanity check that the column you pasted is the one you meant.

Delimiters, prefixes, and line wrapping

Beyond the comma you can join with a semicolon, pipe, tab, space, newline, or any custom string you type, with \t and \n expanded to real characters. A per-item prefix and suffix is applied inside the quotes, which is how you turn home and about into #home, #about for a tag list or CSS selector. For very long results, set a line wrap width so the output breaks after roughly N characters instead of forming one enormous line — the break always lands after a separator, never inside an item.

Privacy and limits

Everything runs client-side in your browser; no list is uploaded. Files you drag in are read locally and capped at 2 MB, and input is capped at 5,000,000 characters with a warning well before that. The share link carries your option settings, and the list itself only when it is short enough to fit in a URL — longer lists are deliberately left out.

Frequently Asked Questions

Is the List to Comma Separated Converter free?

Yes, List to Comma Separated Converter is totally free :)

Can I use the List to Comma Separated Converter offline?

Yes, you can install the webapp as PWA.

Is it safe to use List to Comma Separated Converter?

Yes, any data related to List to Comma Separated Converter only stored in your browser (if storage required). You can simply clear browser cache to clear all the stored data. We do not store any data on server.

How does the List to Comma Separated Converter work?

In the default direction your text is split on every line terminator — CRLF, LF, or a bare CR — so each line becomes one item. The items then run through a cleaning pipeline in a fixed order: trim, drop blanks, remove duplicates, sort, change case, add the prefix and suffix, and finally wrap each item in the quote character. What survives is joined with your chosen delimiter and optionally wrapped in brackets. Reverse the direction and the same pipeline runs after the input has been split on a delimiter instead.

Can I turn a comma separated string back into a list?

Yes — switch the direction to Delimited to list, or press the swap button between the two panes. Auto-detect counts commas, semicolons, pipes, and tabs that sit outside quoted regions and picks whichever is most frequent, breaking ties in that order; the separator it settled on is reported above the result. You can also name the separator yourself, split on any whitespace, or split on a custom string. Line breaks always end an item too, so a delimited file with several rows still comes out one value per line.

How do I build a SQL IN list or a JSON array?

Use the preset cards. SQL IN list sets a single quote, a comma delimiter, and round brackets to produce ('101', '102', '103'). JSON array sets a double quote, a comma, and square brackets to produce ["101", "102", "103"]. Both are just shortcuts for the quote, delimiter, and bracket controls, so you can adjust any part afterwards. Note that JSON array output is only valid JSON when your items are strings — numbers that need to stay unquoted require the quote character set to None.

What happens to quotes that are already inside my items?

That depends on the escape setting, and it only applies when a quote character is selected. Double it follows the CSV convention, so a double-quoted item containing " becomes "", which is what spreadsheets and CSV parsers expect. Backslash escape writes \" instead, which is what JSON and most programming languages expect. Leave as-is does nothing, which will usually produce output that a parser rejects.

Why am I warned that the output may not round-trip?

Because one or more of your items already contains the delimiter you are joining with, and no quote character is set. Joining apple,pie and cherry with a comma gives apple,pie, cherry, which any parser will read back as three items instead of two. Adding a quote character fixes it, and the warning disappears. The tool never blocks on this — it only blocks when the delimiter and the quote character are the same, which cannot produce parseable output at all.

Is my list uploaded anywhere?

No. All splitting, cleaning, and joining happens in your browser with plain JavaScript, and nothing is sent to a server. Files you drag in are read locally and capped at 2 MB, input is capped at 5,000,000 characters, and the share link deliberately carries your option settings plus your list only when the list is short enough to fit in a URL — longer lists are left out of the link entirely.