Duplicate Line Finder
Find repeated nonblank lines in a pasted list.
Play Duplicate Line Finder
Paste lines and inspect repeats with their occurrence counts.
How to use Duplicate Line Finder
Paste lines and inspect repeats with their occurrence counts. All gameplay and calculations run in the browser; there is no mandatory account, game API or score upload.
What this challenge measures
Number of unique duplicates and their frequencies. This result describes performance in this specific exercise; it should not be interpreted as a population ranking.
How to improve with practice
Repeat attempts under similar conditions, compare with your own recent sessions, and favor consistent accuracy over isolated personal records. For fair comparisons keep the same browser, input method and device when possible.
Accuracy and limitations
Matching is whitespace-trimmed and case-sensitive. Paused tabs, varying display refresh rates and browser scheduling can also affect time-sensitive exercises. Browser-local history can be cleared by the visitor at any time.
Frequently asked questions
Is Duplicate Line Finder free?
Yes. You can use it without signing in or paying.
How do I use Duplicate Line Finder?
Paste lines and inspect repeats with their occurrence counts.
What does Duplicate Line Finder report?
Number of unique duplicates and their frequencies.
Are scores scientifically or medically certified?
No. Matching is whitespace-trimmed and case-sensitive.