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Compare Two PDFs
See exactly what changed between two versions.
Processed locally — your files never leave your device
How to use Compare PDFs
- 1
Add the original document and the revised version.
- 2
Click Compare — every page pair is analyzed.
- 3
Review the overlay diff (changes highlighted in red) or flip to side-by-side view.
- 4
Check the per-page text changes listed below each comparison.
About this tool
"Final_v2" arrives and the sender says they "just fixed a typo". Did they? Eyeballing two forty-page PDFs side by side is how changed payment terms slip through. This tool does the comparison mechanically: it renders both documents and diffs them pixel by pixel, so any visual change — moved text, edited numbers, a swapped logo, an added clause — lights up in red.
Each page pair gets a changed-percentage score, so you can scan the summary and jump straight to the pages that differ. The overlay view paints differences in red on top of the page; side-by-side shows both versions whole. Below the visuals, a text-level diff lists lines that were added or removed — the fastest way to read what actually changed.
Pixel comparison has a useful property: it can't be fooled. Changes in scanned documents, images, stamps and signatures are caught just as reliably as text edits, because the comparison looks at the rendered page, not the file's internals.
Frequently asked questions
Can it compare scanned documents?
Yes — that's a strength of pixel-level comparison. Any visible difference between the scans is highlighted, though beware that re-scanning the same paper twice produces tiny alignment differences that register as noise.
What if the documents have different page counts?
Pages present in only one document are flagged as such and shown on their own. Matching pages are compared normally.
What does the percentage mean?
The share of pixels that differ between the two versions of that page. Identical pages score 0%; a re-typeset paragraph might score 2–5%; a fully different page scores high. Even small percentages are worth a look — a changed number is only a few pixels.
Does the text diff understand moved paragraphs?
The text diff flags lines that appear in only one version. A paragraph that merely moved pages will appear as removed from one page and added to another — the pixel view makes such moves obvious.