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About this tool
Identify and remove duplicate lines from lists, code, or logs with custom case-sensitivity and whitespace settings.
Duplicate Line Remover strips repeated lines from any block of text, keeping the first occurrence of each line in its original order and discarding every later copy. It compares lines through a normalisation step you control — case-insensitive matching, whitespace trimming and empty-line removal are on or off by choice — so 'Apple', 'apple' and ' apple ' can count as the same entry or as three different ones. Paste a list, keyword export, log file or code block and you get the deduplicated text plus a count of total lines, unique lines, removed lines and the duplicate percentage.
Open Duplicate Line Remover on AltFTool — it loads instantly in your browser.
Paste your list, log or keyword export into the Original Text box, or press Load Sample.
Switch Case Sensitive Match, Trim Spacing and Remove Empty Lines on or off to decide what counts as the same line.
Check Total Lines, Unique Lines, Removed and Duplicate Pct, then press Copy or Download for deduplicated-text.txt.
Case sensitivity, whitespace trimming and empty-line handling are three independent switches, so 'apple' vs 'Apple' is your call, not a fixed behaviour.
The first occurrence of each line is kept exactly as typed — indentation and capitalisation intact — rather than being sorted or normalised in the output.
Alongside the cleaned text you get total, unique and removed line counts plus a duplicate percentage, which is often the number you actually needed.
By default yes — matching is case-insensitive unless you tick Case Sensitive Match. With that box ticked, 'Apple' and 'apple' are stored as two separate unique lines; with it unticked only the first of the two survives.
The first one, in the order it appears in your input. Later matches are dropped, and the surviving line keeps its original characters — so if trimming is on for matching purposes, the kept line still shows whatever spacing it originally had.
It is removed lines divided by total input lines, expressed as a percentage to one decimal place. Ten repeated entries out of 100 input lines reads as 10.0%, and blank lines count toward the removed total when Remove Empty Lines is on.
No. Deduplication runs in JavaScript in your own browser tab, so pasted content, logs and email lists never leave the device — which matters when the list contains customer data.