What this list comparison tool does
Enter one item per line in one or both of List A and List B. The tool compares the lists as unordered values, so item positions do not matter. It does not provide positional or document diffs.
It shows six result panels:
- Only in A and Only in B list items found on one side only.
- In Both Lists lists items found in both lists.
- Duplicates in A and Duplicates in B list distinct repeated items within each list.
- Combined Unique lists each distinct item from both lists once.
Understand the comparison results
The summary bar reports Only in A, Only in B, In Both, and Combined Unique. Each duplicate entry includes its occurrence count as visible text in the form ×N. A duplicate panel’s badge counts listed duplicate items, not the total number of repeated lines. After results are rendered, an empty panel displays None.
With Ignore case enabled, matching values are grouped together, and the displayed spelling comes from the first occurrence.
Controls, sorting, and copying
- Ignore case - treats "Apple" and "apple" as the same item.
- Trim whitespace - removes whitespace at the start and end of each line before comparison.
- Ignore blank lines - filters empty items when enabled. When it is unchecked, empty lines remain as items after parsing.
- Sort output - choose Original order, A → Z, or Z → A. Original order keeps the first-seen order for each result panel.
Select Copy on a result panel to copy its item values one per line. For duplicate panels, copying omits the visible ×N counts. Copying uses the browser Clipboard API. If access is unavailable or fails, the page reports that and tells you to select the result text and copy it manually.
How to compare two lists
- Enter one item per line in one or both text areas labeled List A and List B. When both inputs contain only whitespace, the page shows Enter items in both lists to compare.
- Set the comparison controls if needed. Results update when either text area or a control changes.
- Review the six result panels and the summary bar.
Paste, upload, or drop list data
Enter list data in the text areas, use Upload to open a file picker, or use Drop file in the corresponding list area. The page reads the first selected or dropped file as text into that list. The shared text-input contract accepts the listed text extensions and MIME type, reports an unsupported file type near the corresponding list, and reports file-read failures with a retry path.
Processing and privacy limitations
Comparison and file reading run in browser JavaScript. This page’s comparison script does not send the entered list contents to a server. The implementation does not define an explicit character-encoding guarantee.
Frequently Asked Questions
Does the order of items matter?
No. The tool treats both lists as unordered collections. An item in position 1 of List A that also appears in position 50 of List B is still counted as being in both lists.
What counts as a duplicate?
An item is a duplicate when it appears more than once in the same list after the Ignore case, Trim whitespace, and Ignore blank lines settings are applied. Duplicate panels show each distinct repeated item with its occurrence count.
Are my lists sent to a server?
The comparison and file reading run in browser JavaScript. The assigned page code does not send the entered lists to a server.