Compare PDF
See exactly what changed between two versions of a document: added words in green, removed words in red, side by side, with a list of every change.
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Simple, practical guidance
How to use Compare PDF
Find every change between two versions of a contract, policy or report without reading both line by line. Follow these steps to get a result you can confidently review, save, and share.
- 1
Upload the original PDF.
- 2
Add the revised PDF.
- 3
Run the comparison.
- 4
Download the report and review the highlighted changes.
Get a better result
Text is compared word by word, so edits are caught even when pages reflow; changes are shown side by side and listed on a summary page.
Know how your file is handled
The file is sent to the configured processing server because this job needs software that a browser cannot provide. Avoid uploading documents you are not permitted to process.
Check before you share
Both files need a text layer, and changes to images, colours or layout alone are not detected.
Questions people ask
Compare PDF FAQ
Clear answers about file quality, privacy, compatibility, and what to expect from the conversion.
What does Compare PDF do?
Find every change between two versions of a contract, policy or report without reading both line by line. It accepts two versions of a PDF and produces a comparison report PDF.
How do I use Compare PDF?
The process is straightforward. Upload the original PDF. Add the revised PDF. Run the comparison. Download the report and review the highlighted changes.
Is Compare PDF available now?
Compare PDF is available now on Big PDF Tools.
Will Compare PDF reduce the quality of my document?
Text is compared word by word, so edits are caught even when pages reflow; changes are shown side by side and listed on a summary page.
Is it safe to use Compare PDF with private files?
The file is sent to the configured processing server because this job needs software that a browser cannot provide. Avoid uploading documents you are not permitted to process.
Can I use Compare PDF on a phone or tablet?
Yes. Compare PDF works in a modern mobile browser: the file is sent to the server for processing, so keep a stable connection and leave the tab open until the job completes.
Is there a maximum file size for Compare PDF?
The practical limit depends on the upload size and the processing server. If a very large file stalls, try a smaller file or split the work into manageable parts.
Does Compare PDF change my original file?
No — your original file stays unchanged. Compare PDF saves a comparison report PDF as a separate download.
How long does Compare PDF take?
Small files usually finish quickly. Large page counts, high-resolution images, complex layouts, upload speed, and server load can all increase how long Compare PDF takes.
Why did my Compare PDF job fail or look different?
Both files need a text layer, and changes to images, colours or layout alone are not detected. Also confirm that the source file is not damaged, uses a supported format, and is not blocked by an unknown password.