Remove Duplicate Lines Online
Paste any list or text block — remove duplicate lines instantly, case-sensitive or case-insensitive. Free, no signup, works in your browser.
Frequently asked questions
How do I remove duplicate lines in Excel?
In Excel: select your data, go to Data → Remove Duplicates. For a text list (not in a spreadsheet), paste it here instead — one item per line, click "Remove duplicates (keep order)", and copy the result back.
How do I remove duplicates in a text file?
Open the file, select all text (Ctrl+A), copy it (Ctrl+C), paste it here, click "Remove duplicates (keep order)", then copy the output and paste it back into your file. Works with any plain text file, CSV list, or log file.
What is the difference between case-sensitive and case-insensitive deduplication?
Case-sensitive: "Apple" and "apple" are treated as different lines — both kept. Case-insensitive: "Apple", "apple", and "APPLE" are all treated as the same — only the first occurrence is kept. Choose case-insensitive when you want to remove duplicates regardless of capitalization.
What does "Keep only duplicates" do?
It shows you which lines appear more than once — useful for auditing a list to find repeated entries. Each duplicate line appears once in the output (the second and subsequent occurrences are hidden, just the line itself is flagged).
Can I remove duplicate words instead of lines?
This tool works line by line. To remove duplicate words within a line, you'd need a different approach — put each word on its own line (replace spaces with newlines), use this tool, then put them back on one line using the remove line breaks tool.
How do I remove duplicates in Python?
Use list(dict.fromkeys(lines)) to remove duplicates while preserving order — this is the idiomatic Python 3.7+ approach. Alternatively, use list(set(lines)) for a quick deduplicate, but note that set() does not preserve insertion order. For case-insensitive dedup, normalize with .lower() before comparing.
How do I remove duplicates in Google Sheets?
Select your data range, then go to Data → Data cleanup → Remove duplicates. Choose which columns to check and whether your data has a header row, then click Remove duplicates. For a plain text list (not in a spreadsheet), paste it here instead — it's faster and doesn't require reformatting into cells.
How do I find duplicates in a list without removing them?
Use the "Keep only duplicates" option in this tool. It shows you every line that appears more than once, so you can review what is duplicated before deciding what to do. This is useful for auditing mailing lists, log files, or any dataset where you want to inspect repeated entries first.
How do I count how many duplicates are in my list?
Run "Remove duplicates (keep order)" and note the line count before and after — the difference is the number of duplicate lines removed. For example, if your list had 200 lines and the result has 180 lines, there were 20 duplicate lines. The tool displays a count of removed lines after processing.
What is the difference between case-sensitive and case-insensitive deduplication?
Case-sensitive treats "Apple" and "apple" as different lines — both are kept. Case-insensitive treats them as the same — only the first occurrence is kept and the rest are removed. Use case-insensitive when working with email addresses, URLs, usernames, or any data where capitalization differences should not be treated as meaningful.
How do I remove duplicates and sort at the same time?
Use the "Remove duplicates + sort A→Z" option. It deduplicates the list and returns the unique lines in alphabetical order in a single step. This is useful when building a clean, sorted reference list — for example, a unique sorted list of tags, domains, or keywords.