BYTETOOLS

Compare Two PDFs

Find what changed between two PDF versions with a word-level diff and a pixel difference view, page by page. Both files stay in your browser.

Original

Drop the original PDFVersion A

Revision

Drop the revised PDFVersion B

Load both files to compare them. Everything is read in your browser — neither document is uploaded.

What is the Compare Two PDFs?

Someone sends back "the updated contract" with no track changes and no summary. Reading both versions side by side to spot a changed number is slow and unreliable — the eye skips over exactly the sort of small edit that matters most.

  • Word-level diff with additions and deletions highlighted in place
  • Pixel difference view for layout and image changes
  • Per-page summary table showing exactly which pages changed
  • Handles files with different page counts and flags pages present in only one
  • Large pages fall back gracefully instead of freezing the tab
  • Both documents are read locally and never uploaded

How to use the Compare Two PDFs

  1. 1

    Drop the original PDF into the left upload area and the revised one into the right.

  2. 2

    Click Compare PDFs and wait while both documents are read and diffed.

  3. 3

    Check the summary tiles for the number of changed pages and the total words added and removed.

  4. 4

    Pick a page from the dropdown — pages are labelled with their change counts — and read the highlighted word differences.

  5. 5

    Switch the View selector to Pixel differences to see changes that do not show up in the text, such as moved graphics.

About the Compare Two PDFs

Someone sends back "the updated contract" with no track changes and no summary. Reading both versions side by side to spot a changed number is slow and unreliable — the eye skips over exactly the sort of small edit that matters most.

This tool compares two PDFs page by page. The word view runs a longest-common-subsequence diff over the extracted text and highlights every addition in green and every deletion in red, in place, so you can read the changed paragraph in context. The pixel view renders both versions of a page and paints every changed pixel red, which catches moved images, restyled headings and other changes that leave the words identical.

Both documents are read in your browser and neither is uploaded, which is what makes this usable on drafts and contracts you are not allowed to send to an online service. A per-page summary table tells you at a glance which pages changed and which are untouched, so on a long document you can go straight to the handful that matter.

Frequently asked questions

How do I compare two versions of a PDF?

Load the original and the revision, then click Compare. The tool extracts the text from both and highlights every word that was added or removed, page by page, with a pixel view for changes the text does not capture.

Why does the word view show nothing when the pages clearly differ?

The page probably has no extractable text — scanned documents are images until they have been through OCR. Switch to the pixel difference view, which compares the rendered pages and works on scans.

What is the difference between the word view and the pixel view?

The word view tells you what the text changed to, which is what you want for contracts and reports. The pixel view tells you what the page looks like differently, which catches moved images, font changes and reflowed layout.

Can it compare documents with different numbers of pages?

Yes. Pages are compared in order, and any page that exists in only one of the two files is listed as such in the summary rather than being reported as a huge change.

Are my documents uploaded to compare them?

No. Both files are read and rendered in your browser, which is what makes this safe for contracts and drafts you cannot send to a third-party service.

Related tools