Remove Duplicate Lines
Paste a list and drop every repeated line, keeping the first occurrence in its original order. Ideal for cleaning order numbers, emails, and keyword lists.
Runs locally in your browser. Nothing is uploaded.
What is Remove Duplicate Lines?
Remove Duplicate Lines is a free online tool that takes a list, one item per line, and deletes every repeated line while keeping the first occurrence of each item in its original order. It is the kind of small cleanup that comes up constantly: order numbers copied from several spreadsheets, email addresses gathered from different forms, keywords merged from multiple lists, or log lines that repeat. Doing it by hand in a long list is slow and error-prone; here it takes one click, and the tool reports exactly how many lines were removed so you can sanity-check the result.
Three options control how lines are compared. Case-sensitive, on by default, treats “Apple” and “apple” as different lines; switch it off and they count as the same line, with the first spelling kept. Trim whitespace strips leading and trailing spaces and tabs before comparing, which catches duplicates that only differ by invisible padding copied from a spreadsheet or a web page. Drop empty lines, also on by default, removes blank lines from the result; switch it off and a single blank line survives as one entry like any other line. The result is never sorted, so the order you pasted is the order you get back, which matters when the list order carries meaning such as priority or chronology.
How to use Remove Duplicate Lines
Paste your list into the top box, one item per line. Set the three options to suit your data, then press Remove duplicates. The cleaned list appears in the result box below, and the status line shows how many duplicate lines were removed plus the before and after line counts. Press Copy result to put the cleaned list on your clipboard. Load example fills in a short list with repeats so you can see the options in action, and Clear empties both boxes.
Frequently asked questions
Which occurrence is kept? Always the first one. If a line appears five times, the first stays where it was and the other four are removed, so the original order of first appearances is preserved exactly.
Why are two identical-looking lines not removed? Usually hidden whitespace or a case difference. Turn on Trim whitespace to ignore padding, or switch off Case-sensitive to treat “Apple” and “apple” as the same line, then run it again.
How large a list can it handle? Processing runs entirely in your browser, so lists of tens of thousands of lines are fine. Extremely large pastes of hundreds of thousands of lines may pause briefly while the page works through them.
Is my list sent to a server? No. The text never leaves your device, so the tool is safe for order numbers, customer emails, and other private lists.