Original text
New text
Comparison rules and view
Paste text into A and B and the differences appear here.
Paste two versions and see which lines were added, removed or replaced — and, inside a replaced line, which words actually changed. It all runs in the page, so contract drafts and internal config files can be compared without leaving your machine.
Questions
Is there a size limit?
5,000 lines per side. Above that, the tool stops with a warning instead of comparing only part of the input. For anything larger, use git diff or a similar command-line tool.
Is my text stored?
No. Everything happens in the page and nothing is sent to a server. Close the tab and it is gone.
What is the unified diff for?
It is the standard "--- / +++ / @@" format that git and patch understand, with three lines of context around each change. Copy it into a review comment, or save it as a patch file.
Can I compare Word or PDF files directly?
No — this compares pasted text, so extract the text first. Formatting differences such as bold or colour are not part of the comparison.
Side-by-side or unified?
Side by side is better for checking which old line became which new one. Unified fits a narrow screen and reads top to bottom when you just want to walk through the changes. The underlying comparison is identical.
For Japanese input on Windows: Asteria