View & Compare PDF

Open, read and compare PDF documents side by side, and control how they display when opened in a PDF reader.

View and compare tools let you read a PDF without installing software, find every change between two versions of a document, and decide how a file opens for the people you send it to. Each file is read on your device and never uploaded.

PDF Viewer opens a PDF, or an image, in any modern browser on Windows, macOS, Linux, ChromeOS, iPhone or Android. It draws pages with pdf.js, the engine Firefox uses for its own viewer, and gives you page thumbnails, zoom from 25% to 400%, text search that highlights every match, printing and a download button. Protected files ask for their password before the pages load. It is for reading only, so there is no editing, and search finds nothing in a scan until it has been through OCR.

Compare PDF puts two versions side by side in two modes. The text view marks changed, added and removed lines and highlights the edited words, ignoring font and colour. The visual view renders each page and paints every area where the pixels differ in red, so it catches a moved image, a new logo or a formatting change that the text view misses, and it works on scans. Visual comparison matches pages by number, so after an inserted page use the text view. You can export a PDF report listing up to 3,000 changes with their page numbers.

PDF Viewer Preferences writes opening settings into a file: a single page or two-page spread, the bookmarks or thumbnails panel, full screen, window options, right-to-left reading and print at actual size, which starts the print dialog at 100% for forms, labels and scale drawings. Adobe Acrobat and Reader follow all of these; browser and mobile viewers ignore some.

Lawyers checking a returned draft, students reading on a borrowed laptop and designers sending a presentation all use this group.

  • PDF Viewer

    Open a PDF or an image in your browser with page thumbnails, zoom, text search and printing. The file is read on your device, not uploaded.

  • Compare PDF

    Compare two versions of a PDF to see changed, added and removed text side by side, or spot visual changes page by page. Runs in your browser.

  • PDF Viewer Preferences

    Choose how a PDF opens: page layout, bookmarks or thumbnails panel, full screen, window options, reading direction and print scaling.

Common questions about view & compare pdf

Can I view a PDF without installing anything?

Yes. PDF Viewer runs in any modern browser on a computer, tablet or phone, and draws pages with pdf.js. It opens password-protected files once you type the password, searches real text and prints through your browser's own print dialog. Closing the tab clears the file from memory.

How do I find the differences between two PDF versions?

Open Compare PDF and add the original as PDF A and the new version as PDF B. The text view lists every changed, added or removed line, and the visual view shows changed areas in red. Export diff report gives you a PDF summary of the changes with page numbers.

Can I compare scanned PDFs?

Yes, with the visual comparison, which works on page images. The text comparison needs a text layer, so for scans it tells you there is no selectable text. Run both files through the OCR tool in the Optimize & Repair PDF group first if you want a word-level comparison.

Why does search find nothing in my PDF?

Search only finds real text, and a scanned document is a set of page images with no text layer. Run the file through the OCR tool in the Optimize & Repair PDF group, then open the new copy in PDF Viewer and search it.

Can I make a PDF open at a two-page spread or in full screen?

Yes, with PDF Viewer Preferences. Pick the page layout and what the reader shows on opening, then save. Acrobat and Reader follow these settings, and Acrobat asks the reader to allow full screen the first time, but browser and mobile viewers may ignore some of them.