Diff two Word (.docx) documents side by side — Pick an original and a modified DOCX. The text of both documents is extracted locally and compared line by line: additions are highlighted in green, removals in red, and changed lines in yellow. Export the result as a standalone HTML page or a plain-text diff. Everything runs locally — no upload, no server, no cloud.
Original document (A)
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Modified document (B)
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Engine: loading local library…
Choose both DOCX files, then click Compare.
Added Removed Changed line
A — Original
B — Modified
Comparison ready
What a line-level diff does (and does not) show
This tool compares documents line by line: one paragraph of the document is one line of the comparison, so a single changed word marks the whole line as changed. That is coarser than Word's own revision tracking, which stores word-level edits inside the file — this page only reads your two files and never writes changes back into them.
Compare works best on two versions of the same source document; two unrelated documents usually come out almost entirely red and green. To edit the result use the Word Viewer / Editor; to join documents use Word Merge.
