Duplicate Line Remover & List Sorter
Paste a list, one item per line, and remove duplicates, sort it ascending, descending, or randomly, sort by how often each item repeats, or find and count duplicates.
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About this duplicate line remover
Paste any list — email addresses, keywords, to-do items, code identifiers, spreadsheet exports — one entry per line, and this tool strips out repeats while keeping everything else exactly where it was. That last part matters: unlike a plain sort-and-dedupe, the result preserves your original line order by default, only removing the lines that were genuinely redundant, since reordering a list you didn't ask to reorder is its own kind of surprise.
Two settings quietly cause most of the "why didn't this catch my duplicate" confusion in simpler tools. Case sensitivity: "Apple" and "apple" are different lines by default, since that's the literal, exact-match behavior most people expect first — check "case-insensitive" if you want them treated as the same entry. Whitespace: a line with an invisible trailing space looks identical to one without, but is technically a different string, which is why "ignore leading/trailing whitespace" is checked by default — most messy, copy-pasted lists benefit from this, though you can turn it off if you need byte-exact comparison.
When a line repeats with small differences in casing or spacing, "keep first occurrence" preserves whichever version you listed earliest, while "keep last occurrence" preserves whichever version came later — useful when a list has been edited or appended to and the later entry is the corrected or more current one. Either way, the survivor keeps its original position in the list; nothing is reshuffled unless you also turn on alphabetical sorting.
Switching "Show" to "duplicates only" flips the tool into an audit mode: instead of the cleaned list, you see exactly which lines would have been removed, which is useful for reviewing before you commit to deleting anything from an important list. "Find duplicates" is a related but different view: rather than showing every removed instance, it lists each repeated value exactly once, which answers "which entries are duplicated?" instead of "which specific lines would be dropped?" — useful when you care about which values repeat rather than how many extra copies exist. "Deduplicate with count" keeps one copy of every unique entry but prefixes it with how many times it appeared, turning a raw list into a tally — a plain export of survey answers, votes, or repeated log entries becomes a readable frequency count with nothing more than a paste and a click.
Sort order works independently of all of that: leave it on "keep original order" to preserve exactly the sequence you pasted, or choose ascending, descending, a random shuffle, or "by number of occurrences" to bring the most (or least) common entries to the top — genuinely useful paired with "deduplicate with count," since sorting a tally by frequency is usually more useful than sorting it alphabetically.
Only your settings are remembered between visits — never the list itself, since people paste all kinds of personal and professional data into a tool like this.
Frequently asked questions
Does this catch duplicates that differ only in capitalization?
Only if you check "case-insensitive." By default, "Apple" and "apple" are treated as different lines, since exact matching is the more predictable default. Turn the checkbox on to treat different capitalizations as the same entry.
What's the difference between "keep first" and "keep last" occurrence?
When the same entry appears more than once with slightly different casing or spacing, "keep first" preserves the earliest version you listed, and "keep last" preserves the most recent one — useful if a later entry in your list is an edited or corrected version of an earlier one.
What does "duplicates only" show me?
The lines that would be removed if you ran the normal deduplication — useful for double-checking exactly what's about to be dropped before you commit to using the cleaned-up list.
Will this change the order of my list?
No, not unless you turn on "sort result alphabetically." By default, every kept line stays in its original position; only the duplicate lines are removed.
What's the difference between "duplicates only" and "find duplicates"?
"Duplicates only" shows every removed instance, so a value appearing 3 times shows up twice in the result (the copies that would be dropped). "Find duplicates" instead lists each repeated value exactly once, answering "which entries repeat?" rather than "which specific copies would be removed?"
Can I sort a list by how often each item appears?
Yes, choose "by number of occurrences" from the sort order menu. It's especially useful combined with "deduplicate with count," turning a raw list into a tally sorted from most to least common.
Is my list saved or uploaded anywhere?
No. Only your option settings (case sensitivity, whitespace handling, and so on) are remembered locally for convenience — the list you paste is never saved or sent anywhere.