Find Duplicate Lines
Paste text and see which lines repeat, and how many times — most frequent first. Optional case-insensitive and whitespace-trim matching. Runs in your browser; nothing is uploaded.
About this tool
Find Duplicate Lines scans pasted text and lists the lines that appear more than once, along with how many times each occurs — sorted most-frequent first.
- Ignore case — treat
Foo,foo, andFOOas the same line. - Trim whitespace — ignore leading/trailing spaces and tabs when comparing,
so
itemanditemcount together.
It also reports the total number of lines and the number of unique lines. Everything runs locally in your browser via WebAssembly — your text is never uploaded.
Handy for
- Spotting repeated entries in a list, export, or log.
- Quality-checking a deduplicated file (there should be none left).
- Finding the most common repeated value in a column of data.
Want to remove the duplicates instead of just counting them? Use a dedupe tool; this one is for finding and counting repeats.
FAQ
In what order are the duplicated lines listed?
Most frequent first. When two lines occur the same number of times, the one that appeared earlier in your text is listed first, so the ordering is stable and predictable.
If "Ignore case" merges Foo, foo and FOO, which spelling shows in the results?
The first-seen form. The tool keeps the line exactly as it first appeared
(e.g. Foo) as the display text, while counting all case variants toward the
same total.
Why aren't `item` and ` item ` counted as the same line?
By default lines are compared byte-for-byte, so surrounding spaces or tabs make them different. Turn on Trim whitespace to strip leading/trailing whitespace before comparing — then both count together and the trimmed form is displayed.
What do the total and unique line counts mean?
Total lines is every line in the input (including blanks). Unique lines is the number of distinct lines after your chosen normalization (case folding and/or trimming). If nothing repeats, the tool simply says no duplicate lines were found.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool find-duplicate-lines "Paste lines to check for duplicates…"New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/find-duplicate-lines/?text=Paste%20lines%20to%20check%20for%20duplicates%E2%80%A6&ignore_case=true&trim=trueMachine-readable descriptor: tool.json — title + parameters JSON Schema for agents.