Compare and merge lists
Paste two lists to see what is new, what is missing, what they share, and a de-duplicated merge.
Processed in this page’s memory. No upload or saved drafts. Leaving or reloading clears the lists.
Comparison results
List A
- Input lines
- Blank lines ignored
- Non-empty items
- Unique items
- Duplicate lines
List B
- Input lines
- Blank lines ignored
- Non-empty items
- Unique items
- Duplicate lines
First line numbers start at 1 and include blank lines. Occurrences include the first item. Each list’s repeated items appear once.
Only in A —
No items to copy
Results appear after comparison.
Only in B —
No items to copy
Results appear after comparison.
Shared items —
No items to copy
Results appear after comparison.
Merged list —
No items to copy
Results appear after comparison.
How it works
Does this compare line by line?
No. It checks whether each item exists in the other list. The two lists do not need the same order. This is not a line-by-line text diff.
What makes two items match?
By default, outer spaces are trimmed and matching is case-sensitive. Turn trimming off to preserve outer spaces. Ignore case uses JavaScript’s toLowerCase key. It does not normalize spelling, synonyms, NFC, or NFKC, or decide whether records represent the same person.
What happens to duplicates in one list?
Each list keeps the first item’s text and line number and counts duplicate lines. Shared items use A’s first spelling. The merged list keeps A’s order, then adds items from B that have not appeared in A.
Are the lists uploaded or saved?
The lists are calculated in this page’s memory without uploading or saving drafts. Leaving or reloading clears them. Your environment manages the OS clipboard, browser extensions, and the destination where you paste copied text.
Does an empty result mean failure?
No. Valid lists may have no items in a category. Even two blank lists are valid. Empty results say “No matching items” and have no content to copy.