Compare PDF

See what changed between two versions of a PDF.

Import two PDFs

PDF
Merge PDF Combine PDF files and images in the order you need. Split PDF Split a PDF into separate files. Extract PDF Pages Save chosen pages as a new PDF. PDF to Images Save PDF pages as JPG, PNG or WebP. Images to PDF Turn images into one PDF. Convert to PDF Turn documents, spreadsheets, presentations and images into PDF.

How to compare two PDFs

Docs

Drop the old version first and the new one second, or swap them later.

Compare

Words, not pixels

The text of both files is compared word by word over the whole document, so a paragraph that pushes the rest to the next page does not mark every page after it.

Moved text is moved

A section that moved shows as moved on both sides, not as deleted in one place and added in another.

Both sides on the same text

Sync scroll follows the matching text, so an inserted page or paragraph never puts the two columns out of step.

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Images, drawings and layout

A replaced image or a changed chart is outlined. Visual compares the pages pixel by pixel for layout and colour.

Scans too

Use OCR reads both files first, so two scanned versions can be compared word by word.

Frequently asked questions

How do I compare two PDF files?

Drop the old version, then the new one. Every change is marked on both sides and listed. Select Save report for a PDF of it.

Which file is the old one?

The first file you drop. Swap turns them round.

Does it work with scanned documents?

Yes. Turn on Use OCR and both files are read before they are compared.

Will a different font show as a change?

No. Text compares the words. Visual shows where the pages look different.

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Are my files uploaded?

No. The files stay in your browser and never leave your device.

Is it free?

Yes. No account and no usage limits.

Technical details

Text

The words of every page are read in reading order with their place on the page, right-to-left and Chinese or Japanese text included. Both documents are compared as a whole with a patience diff, Myers for the small gaps, and moved runs are found among the removed and added ones.

Visual

Matching pages are drawn at 60 dpi and compared pixel by pixel. Edges drawn one pixel apart are not counted, and what differs is grouped into regions.

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OCR

Tesseract 5 reads every page of both files at 300 dpi in your browser, with the languages of the script it finds.

Report

A summary of every change, then each pair of pages side by side with the marks, saved as one PDF.