This tool removes repeated lines from a list and keeps the original order of the lines that remain. It is useful for cleaning email lists, keyword exports, log excerpts and any pasted column of text.
Your data is processed locally in your browser and is not uploaded to our server.
Key = line, optionally trimmed and lowercased
Each line is converted to a comparison key. With “ignore case” enabled, “Apple” and “apple” share a key and count as duplicates; without it they remain separate.
Keep first = first occurrence; keep last = last occurrence, in original order
The output preserves the original line order. Keeping the last copy changes which value survives, not the position of the remaining lines.
A pasted list contains repeated keywords and blank lines.
Two unique keywords remain. Because case is ignored, “apple” and “Banana” win as the first occurrences.
A list of prices where the last entry is the current one.
The repeated 10 is kept at its later position, and the earlier duplicate is dropped.
With trimming off, a trailing space makes two otherwise identical lines different. Turn trimming on when the list comes from a spreadsheet or a PDF copy.
Empty lines can be kept or removed independently of duplicate checking. Removing them is usually what you want before counting entries.
Deduplication never sorts the list. If you also need alphabetical order, use the sort lines tool afterwards.
It checks the whole list, not just neighbouring lines. A duplicate anywhere in the input is detected.
By default it is not: “Apple” and “apple” are treated as the same line. Untick “Ignore case” to keep them as separate entries.
The first occurrence is kept by default. Switch to “Keep last” if the later line has the value you want to preserve.
No. The output keeps the original order of the lines that survive, whether you keep the first or the last copy.
No. All processing happens in your browser, so the list never leaves your device.