Free Online Duplicate Line Remover
Remove duplicate lines and keep the first occurrence.
0 lines
0 lines
Duplicate and cleanup options
Everything runs in your browser. Case sensitivity, trimming, and empty-line handling are applied before
duplicates are compared, so Apple and apple count as the same entry unless you
enable case-sensitive matching.
About the Duplicate Line Remover
Duplicate lines creep into lists through copy-and-paste, merged exports, repeated form submissions, and manual data entry. This tool removes them while preserving the content you want to keep. Paste your list, choose whether to keep the first or last occurrence, and the cleaned list updates immediately. You can also trim whitespace, ignore empty lines, compare case-sensitively, and sort the final result.
Keeping the first or the last occurrence
When a line appears more than once, the two copies are identical after normalization, but their positions may matter. Keeping the first occurrence preserves the order in which each value originally appeared. Keeping the last occurrence is useful when later entries are more authoritative, such as a list where newer imports are appended at the bottom. The tool removes only the duplicate copies, not the line you chose to keep.
Normalization options
- Trim whitespace: removes leading and trailing spaces and tabs before comparing, so
appleandapplematch. - Ignore case: when case-sensitive matching is off,
Appleandappleare treated as duplicates. - Empty lines: when enabled, blank lines are dropped before duplicate detection and do not count as repeated values.
- Sorting: optionally sort the cleaned list alphabetically in either direction after duplicates are removed.
These options are applied in a fixed order: lines are split, trimmed, empty lines are removed, keys are normalized for case, duplicates are removed, and finally the result is sorted. The statistics update at every step so you can see exactly how many lines were affected.
Reading the statistics
The badges show the number of input lines, how many duplicates were removed, how many blank lines were dropped, and how many unique lines remain. The input count is based on the raw text before trimming, while the output count reflects the final cleaned list. If you clear the input, the output and all counters reset to zero.
Privacy and file handling
The entire operation happens locally in JavaScript. Nothing is uploaded to a server, which makes the tool safe for customer lists, email addresses, product codes, and other private data. The download button creates a plain text file on your device, and the copy button places the cleaned list on your clipboard for pasting into a spreadsheet or editor.
Frequently asked questions
Does the tool remove duplicate words within a line?
No. It compares whole lines. If you need to deduplicate words, split the line into separate lines first or use a word-level tool.
Why did two visually identical lines survive?
They may contain different invisible characters, such as a non-breaking space, a tab, or a trailing carriage return. Enable trimming and check the source text in a Unicode inspector if the problem persists.
Can I keep the list order and still sort?
Sorting replaces the original order by design. Choose “Keep original order” if position matters, or sort first and then deduplicate in a separate pass if you need both behaviors.