Document Diff Viewer
Two versions
Summary
Line diff
Unified patch
=================================================================== --- original +++ revised @@ -1,3 +1,4 @@ -The committee met on Tuesday. -The proposal was rejected. +The committee met on Tuesday morning. +The proposal was accepted. +Three new members joined the working group. The next meeting is in June. \ No newline at end of file
Scope and limits
The line view keeps the old and new line numbers of every row so you can move between two drafts; the word view shows the changed runs inside otherwise identical text. Both use the standard diff algorithm and are computed in your browser.
It compares text, not documents: there is no file upload, no history, no three-way merge and no XML or DOCX handling, so paste the plain text of each version. It reports what differs, not which version is better.
The document diff viewer compares two drafts line by line or word by word, shows a stats summary of what changed, and writes a unified patch — all locally, with nothing uploaded.
What is Document Diff Viewer?
A document diff viewer answers one question quickly: what changed between these two versions? Two text areas take the original and the revised draft, and the comparison runs immediately, in the browser, with no upload and no history kept. The result comes in three layers — a visual diff you can read, a stats summary that quantifies the change, and a unified patch you can copy.
The line view aligns the two drafts and marks each row as unchanged, added or removed, carrying the old and new line numbers so you can move between the versions. The word view zooms in on the same change and highlights the runs of words that differ inside lines that are otherwise identical, which is what you want when a sentence has been edited rather than replaced. Switching between the two views is a single control and neither costs a round trip.
That pairing is what makes the tool useful for revision. Comparing two drafts line by line catches a paragraph that was moved, split or deleted; comparing them word by word catches the smaller edit — a reworded clause, a changed number, a softened claim — that a line view would show only as a changed line. Reading the same change both ways is often how you decide whether an edit is cosmetic or substantive. Paste the two versions, read the summary, then switch the view to confirm the specific change you care about. The two panes accept text from anywhere — a notes app, an email draft, a code editor — because the comparison runs on characters, not on a file format. Nothing is transmitted at any point, so even a sensitive draft can be compared here.
The summary is deliberately blunt. It reports how many lines were added and removed, how many words were added and removed, and a percentage of unchanged text, so a large-looking edit that only touched punctuation reads differently from a genuine rewrite. Those four numbers and the similarity figure are usually enough to decide whether a revision needs a careful read or a glance.
The unified patch is the familiar machine-readable form, with context lines and hunk headers, copyable or downloadable for a commit message, a code review or a note to a collaborator. It is generated from the same comparison, so the patch and the visual diff can never disagree. Because the whole thing is client-side, you can paste text you would not upload to a service — a private draft, a contract, a set of notes — and nothing leaves the tab.
What it does not do is as important. It compares text, not documents: there is no file upload, no DOCX or PDF parsing, no three-way merge and no stored version history, so you paste the plain text of each version. It reports what differs, never which version is better, and it cannot tell a deliberate edit from a typo. For a working draft that is exactly the right scope: the tool tells you precisely where the two texts part company and leaves the judgement to you.
How to use Document Diff Viewer
- Paste the original text into the first pane and the revised text into the second.
- Choose line by line for wholesale changes or word by word for fine edits.
- Read the summary: lines and words added and removed, and how much is unchanged.
- Scan the marked rows, then copy or download the unified patch.
When to use Document Diff Viewer vs related tools
Use the document diff viewer whenever two versions of the same text exist and you need to see the difference rather than read both. When the drafts are Markdown, the Markdown Editor renders one of them so you can read the change in context, and for a quick count of how much longer the new version is, the Word Count Tool gives the totals.
When the change you are checking is a rewrite rather than a comparison — words you lean on too often, or passages that read heavily — the Overused Word Finder looks at a single text instead of a pair.
Privacy & Security
This tool runs entirely in your browser — no data ever leaves your device. There is no server round-trip, no upload, no logging, and no account required. Your input is processed locally using client-side JavaScript and is never stored, transmitted, or accessible to anyone else. When you close the tab, everything disappears.