How to use the Remove Duplicate Lines
1. Paste your text (one item per line) into the input box.
2. Toggle options for trimming whitespace and case sensitivity.
3. The deduplicated result appears instantly in the output box.
What is it?
Duplicate line removal is a common data cleaning task when processing log files, email lists, keyword lists, or exported data. This tool processes text line-by-line, keeping only the first occurrence of each line and discarding repeats.
With "Trim whitespace" enabled, lines that differ only by leading/trailing spaces are treated as duplicates. With case-insensitive mode, "Apple" and "apple" are treated as the same line. The order of remaining lines is preserved from the original input.
Example
apple banana apple orange banana grape orange
apple banana orange grape
3 duplicates removed — first occurrence of each line is kept, original order preserved.
Benefits
Deduplicate large lists from exports and log files in one step
Remove repeated entries from database exports, server logs, or CSV files without writing a script or opening a spreadsheet.
Clean up merged lists that inevitably contain repeated items
Combining data from two sources always creates duplicates — remove them instantly before any further processing.
Prepare unique word, tag, or ID lists for indexing
Uniqueness is required before building sets, maps, or search indexes — deduplicate first to avoid counting entries twice.
Count unique items in a large list instantly
The line count after deduplication tells you exactly how many distinct items exist in any list.
Frequently asked questions
Does this preserve the original order?
Yes. The first occurrence of each line is kept, maintaining the original order.
Is there a line limit?
No hard limit. Very large inputs (millions of lines) may be slower due to browser memory constraints.