PDF Compare
Compare two PDFs side by side: changed words, form values and parts that look different are highlighted on both pages, and a strip between them shows where all the changes are, so you can see at a glance what was added, removed or rewritten. Runs in your browser with no upload.
What is PDF Compare?
PDF Compare shows two versions of a document side by side and highlights the differences in their text: a contract before and after review, a revised quotation, an updated manual. The PDFs are read in your browser and nothing is uploaded.
How to use
- Drop the original PDF on the left and the revised PDF on the right (or click to choose them). Password-protected PDFs ask for the password.
- The changes are highlighted on the pages: red on the left is text that was removed or replaced, green on the right is text that was added or is the replacement, and blue on both sides is a part that looks different although the text is the same (an image, a stamp, a line, or text drawn as an image).
- The strip between the two documents shows where all the changes are, from the top of the document to the bottom: yellow marks are rewrites, green additions, red removals and blue differences in appearance. The shaded part is what you are looking at now. Click a mark to jump to that change, or click anywhere in the strip to scroll there. Both sides scroll together.
- Use ▲ / ▼ at the top (or the P / N keys) to jump to the previous or next change. Click a highlight to select that change. The top bar shows the old and new text of the selected change.
- ⇄ swaps the two PDFs.
How the text is compared
- The text is compared word by word (Chinese, Japanese and Korean character by character), so a change is shown even when the lines wrap differently.
- The values typed into form fields and the checkboxes are compared as text too.
- Spaces and line breaks are ignored; letter case and punctuation are compared.
- Pages with the same number and size are also compared as images, to find changes that are not in the text: images, stamps and signatures, lines, colors, and text drawn as an image. Up to the first 300 pages are compared this way.
- Scanned PDFs (pictures of pages) have no text, so only how the pages look is compared.
FAQ
Are my PDFs uploaded?
No. Both PDFs are opened and compared in your browser. They are saved in this browser's storage with the tool (up to 20 MB in total) so they are still there after a reload; turn off Keep files in the tool's settings to not keep them.
Why is a whole paragraph marked as changed?
When most of the words in a part of the document are different, the whole part is shown as one change. Very long documents with many changes may be compared in larger pieces.