Duplicate Line Remover
Paste a list and remove duplicate lines while keeping the first or last occurrence. Toggle case sensitivity and whitespace handling.
How to use: remove duplicate lines from a list
Strip duplicate lines from any list with case-sensitivity, whitespace, and first-vs-last controls.
- 1
Open the Duplicate Line Remover
Go to makemytxt.com/duplicate-line-remover. There is nothing to install or sign up for.
- 2
Paste your list
Paste any list — emails, IDs, error logs, CSV rows. Each line is treated as a single record for comparison.
- 3
Choose comparison options
Decide whether the comparison is case-sensitive, whether each line is trimmed before comparing, and whether blank lines should be dropped.
- 4
Pick keep-first or keep-last and copy the result
Keep the first or the last occurrence of each duplicate. The summary shows how many duplicates were removed; use Copy or Download to save the deduped list.
Frequently asked questions
- Does the order of the original list matter?
- Yes. The deduper preserves the original order of the lines it keeps. With "keep first" the first occurrence wins; with "keep last" the last occurrence wins. Either way, surviving lines stay in their original relative positions.
- How does it treat lines that differ only in whitespace?
- When "Trim each line before comparing" is on, " apple " and "apple" count as the same line. Turn it off to treat them as different. Trimming also normalizes the kept line so the output has no stray whitespace.
- Will it dedupe across different cases like "Apple" and "apple"?
- Only when "Case sensitive" is unchecked (the default). Turn it on to keep mixed-case duplicates separate — useful for case-significant identifiers like API keys.
- Is the original list sent anywhere?
- No. The deduper runs entirely in your browser using a hash set. Nothing is uploaded, logged, or transmitted.