Duplicate Line Remover — Delete Repeated Lines

How to use Duplicate Line Remover — Delete Repeated Lines

Three simple steps, with your content kept on your device.

Built for useful work

Fast, focused, and made to be clear on every screen.

How to remove duplicate lines online

Paste your list into the input, choose how lines should be compared, and select Remove duplicates. The tool keeps the first occurrence of every distinct line and drops each later repeat, so the surviving order matches the order you pasted.

The statistics under the result show input lines, output lines, and how many were removed, which makes it easy to confirm the cleanup did what you expected before you copy the output.

Nothing is installed and no account is required. The whole list is processed by JavaScript inside the current tab, so even long exports stay on your device.

Matching options explained

Ignore case treats Apple and apple as the same line. The text of the first occurrence is what survives, so the capitalization you originally used is preserved in the output even though the comparison ignored it.

Trim whitespace ignores leading and trailing spaces and tabs when comparing. This matters more often than people expect: lines copied from spreadsheets, PDFs, or chat apps frequently carry invisible trailing spaces that would otherwise make two identical-looking entries count as different.

Both options are independent, so you can compare strictly, loosely, or anywhere in between. When a deduplication run removes fewer lines than you expected, enabling trim whitespace is usually the fix.

Blank lines and sorting

Remove empty lines is enabled by default because blank rows are almost always noise in a list. Turn it off when the blank lines are meaningful — for example when they separate paragraphs or logical groups you want to keep.

Sort final lines applies an alphabetical sort after deduplication. Leaving it off preserves the original order, which is the right choice for logs, ranked lists, or anything where sequence carries meaning. Turning it on is useful when you want a clean reference list you can scan quickly.

Cleaning lists, logs, and keyword sets

Email and address lists collected from several sources are the classic case. Merging two exports almost always produces overlap, and deduplicating before an import prevents duplicate records downstream.

Log files and error dumps repeat the same line hundreds of times. Removing duplicates collapses the noise so the distinct problems become visible immediately.

Keyword and tag lists benefit too. SEO keyword exports, product tags, and category lists accumulate near-identical entries, and a deduplication pass with ignore case enabled produces the canonical set.

Why order preservation matters

Many deduplication tools sort as a side effect, which quietly destroys information. If your list is ordered by priority, frequency, or time, sorting it alphabetically makes the result useless for the original purpose.

This tool keeps the first occurrence in place by default, so a list ordered by search volume, timestamp, or manual ranking survives the cleanup intact. Sorting stays available as an explicit choice rather than an unavoidable consequence.

Related text tools

Deduplication is usually one step in a longer text workflow. The Text Diff Checker shows exactly what differs between two versions of a list, which is useful for confirming what a cleanup removed.

The Case Converter normalizes capitalization before comparison when you want the output itself to be consistent, and the Word Counter reports line, word, and character totals for the cleaned result.

Every one of these tools runs entirely in the browser, so a full clean-compare-measure pass never sends your list anywhere.

Frequently asked questions