Duplicate Line Remover (2026) - Dedupe Lines Online

Dedupe before import, not after the bug ships

CSV paste into Shopify, Mailchimp, or a cron allowlist often carries duplicate rows from merged spreadsheets. This tool strips repeats while keeping the first seen order so priority stays intact.

Demo input: apple, banana, apple, cherry, banana, date. Output: apple, banana, cherry, date. Removed: 2. Stats cards show input lines, unique lines, and removed count.

Copy writes the output textarea only.

Combine with case and text utilities

Normalize casing first with the Case Converter if duplicates differ only by case and ignore-case is off.

After dedupe, count lines or words with the Word & Character Counter if a brief caps list length.

Developer logs may need the Regex Tester for pattern-based filtering; this page is exact line match only.

When exact match is the wrong tool

Near-duplicates ("apple" vs "apples") stay separate. Fuzzy dedupe belongs in a spreadsheet or script.

Single-line comma lists are one line. Split to rows first (Find/Replace comma to newline), dedupe, then rejoin if needed.

For JSON arrays, use the JSON Formatter and Minifier to validate structure before manual line edits.

Frequently Asked Questions (FAQ)

How is order preserved?

The first time a line key appears, it is kept. Later identical lines are dropped. Example: apple, banana, apple becomes apple, banana. Removed count = 1.

What does trim whitespace do?

When checked, leading and trailing spaces are ignored for matching. " apple" and "apple" dedupe together. The kept line stays as originally typed on first occurrence.

What does ignore case do?

Matching treats "Apple" and "apple" as duplicates. First occurrence wins. Turn off for case-sensitive lists like base64 strings or Unix paths.

Are blank lines removed?

Blank lines after trim are kept as separate empty lines unless they duplicate another empty line key when trim is on.

Duplicate Line Remover