Remove Duplicate Lines

How to remove duplicate lines

1. Paste a list with one item on each line.
2. Choose whether capitalization, outer spaces and empty lines affect matching. Exact match and Flexible match set the two comparison options quickly.
3. Review the kept and removed totals, then compare the first few results with the source.
4. Copy or download the unique lines shown in their original order. Use result as input when another reviewed pass is useful.

Matching examples

Preserve order

For “Beta, Alpha, Beta,” the result is “Beta, Alpha.” The first occurrence stays where it was.

Ignore letter case

When enabled, “Apple,” “apple” and “APPLE” are treated as the same line.

Ignore outer spaces

Lines such as “Item” and “ Item ” match, but the first line's original spacing is preserved in the result.

Exact match shortcut

Letter case and outer spaces both count. “Apple” and “apple” remain separate, as do “Item” and “ Item ”.

Flexible match shortcut

Letter case and outer spaces are ignored together. The first spelling and spacing still become the kept version.

Practical duplicate-removal workflows

Email or username list

Flexible matching can catch capitalization and accidental padding. Review carefully because some systems treat case as meaningful.

Keyword collection

Ignore outer spaces to remove copy-and-paste padding. Enable case-insensitive matching only when uppercase variants do not carry a separate intent.

Ordered task list

Keep exact matching when repeated wording with different capitalization is intentional. The tool retains the first position of every surviving row.

Export with spacer rows

Turn on Remove empty lines when blank rows are only export noise. Leave it off when one blank row separates meaningful sections.

Second review pass

After a conservative exact pass, choose Use result as input and enable flexible matching. The updated totals then show only what the broader pass removes.

How the first occurrence is chosen

The tool reads from top to bottom and keeps the first line for each comparison key. Later matches are removed. It does not choose the shortest, newest or most common version, so put the preferred spelling first when you can control the input order.

Comparison options affect only the key used to detect a match. They do not rewrite the kept line. For example, with flexible matching, “ Featured Item ” can remain exactly that way if it appears before “featured item.” Use Text Cleaner afterward only if the surviving formatting also needs normalization.

What counts as a complete line

Every row between line endings is compared as one value. Words inside a row are not compared separately, and near-duplicates such as “colour” and “color” remain distinct. Punctuation, internal spaces, emoji and accents matter unless they are part of the specific case or outer-space options.

Empty lines and trailing line breaks

An empty row is a line value too. With Remove empty lines off, the first empty row is kept and later empty rows are removed as duplicates. A trailing line break can therefore create a final empty line in the input count. Turn on Remove empty lines when that structural row is not useful.

Review totals without losing context

The summary reports input lines, kept lines and removed lines. A large removed count deserves a spot check before the result replaces a source file. Keep the original in the first box until the output looks right; moving the result back into the input cannot restore discarded rows.

Responsible use

Duplicate removal is useful for lists, test data and editorial cleanup, but it is not record reconciliation. Two identical lines can represent separate people, votes, transactions or events. Do not deduplicate evidence or business records without a stable identifier and an approved data process.

Limits and privacy

The input is limited to 250,000 characters and is processed only in this browser. Nothing is uploaded or saved by the tool. It compares complete lines; it does not sort them, validate addresses or look for similar wording inside a line.

Common questions