PDF Tools

PDF Diff Viewer

Compares two PDFs on structure and document properties, not on content. It checks page count, each page's size, and the title, author, creator and producer fields, then downloads a plain-text report listing the differences.

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Process

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Up to 2 files

Compare two PDFs:

Upload exactly 2 PDF files
Compare metadata (title, author, etc.)
Compare page counts and sizes
Generate detailed comparison report

Tip: Results are saved as a text report file.

How to Use

1Add exactly two PDFs to the upload area. The first file you add is File 1 and the second is File 2.
2Click Compare PDFs.
3Download comparison-report.txt.
4Open the report: it lists both files' name, size, pages, title, author, creator and producer, then the differences found.

About this tool

Updated September 19, 2026

It compares structure, not content

Two PDFs are checked on page count, each page's dimensions, and the title, author, creator and producer properties.

The report lists every difference it finds across those points: a page present in one file and not the other, a page whose size changed, or a property that differs. What it never does is read the words on the page. A sentence rewritten, a figure changed or an image swapped will not appear in the report, because no text or visual comparison takes place. Knowing that boundary is the difference between a useful check and a false reassurance.

The questions it answers well

Is this the same document? Did a page get added, dropped or resized? Did these come out of the same program?

Those are real questions and this answers them quickly. Two files that claim to be the same version but differ in page count are obviously not the same. A page whose dimensions changed usually means the document was re-exported or run through a conversion. Differing creator or producer values tell you the two files came from different software, which often explains formatting differences you can see but cannot account for.

Identical reports do not mean identical files

A report with no differences means the structure matches. The text could still be completely different.

Two documents with the same number of pages, the same page sizes and the same properties will come back clean even if every paragraph was rewritten. This is the one result that misleads if you forget what the tool does, so treat a clean report as a reason to keep looking rather than a conclusion. To find changed wording you need software that extracts and compares text, which is a different job from this one.

Why fields sometimes show as Unknown

Many PDFs simply have no title or author stored, so both files can show Unknown and count as matching.

Document properties are optional and frequently left blank by whatever produced the file, or deliberately cleared before sharing. When both sides are empty the comparison finds no difference, which is accurate but carries no information. The page-level checks are the more dependable part of the report for that reason.

Features

Needs exactly two PDFs (maxFiles is 2); with fewer than two it shows an error
Compares page count, per-page width and height (rounded to whole points), title, author, creator and producer
Reports pages that exist in only one document
Output is a plain .txt report, not a visual side-by-side view
Encrypted PDFs are loaded with encryption ignored so structure can still be read
Runs in your browser; the files are not uploaded

FAQ

Does it show what text changed between two versions?

No. It does not read page text or render the pages. Two PDFs with the same page count, sizes and metadata but different wording will be reported as having no differences. The report says so at the bottom.

Why does the report say Unknown for some fields?

If a PDF has no title, author, creator or producer set, the report shows Unknown for that field. Two files that both lack a field will show as matching.

What differences does it actually catch?

Different page counts, pages whose sizes differ by at least a point, pages present in only one file, and different title, author, creator or producer values. It is useful for spotting that a re-exported file changed page size or lost a page, not for proofreading.

Are my PDFs uploaded?

No. Both files are read and compared in your browser.

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