Compare PDFs

PDF ToolsNewPremium

Find the text differences between two PDFs.

Nothing Is UploadedRuns In This Browser TabNo Account Needed

How It Works

1

Upload / Input

Select your files or paste your content to get started.

2

Process

The work happens in this browser tab. Your file never leaves your device, so nothing is queued, stored or transmitted.

3

Download / Result

Get your results instantly. Download files or copy output in one click.

Features

Compares the real text of both documents
Line-level differences, grouped by page
Additions and deletions marked separately
Side-by-side previews of both files
Document properties compared as well
Client-side processing

How to use Compare PDFs

  1. Add both documents

    Load the original and the revised version. Both stay on your device.

  2. Run the comparison

    Differences are detected and highlighted so you can see what changed between the two.

  3. Work through the differences

    Step through each one rather than scrolling — it is easy to miss a single changed number.

  4. Record what you found

    Note the material changes somewhere outside the tool before you close it.

When to use Compare PDFs

  • Checking what a counterparty altered in a returned contract
  • Confirming which clauses changed between two drafts of an agreement
  • Verifying a supplier sent the revision they said they did
  • Reviewing edits in a document you do not have the source file for

FAQ

Differences in the text. Each page is read as lines and compared with the matching page of the other document, so you get the lines that were added and the lines that were removed. Changes to images, logos and signatures are not detected, and there is no visual overlay of the two pages — differences are reported as text.
Not as they stand. A scan has no text layer, and the tool says so rather than reporting that the documents match. OCR PDF will read both scans, but it hands back plain text rather than writing a text layer into the PDFs, so there is nothing to load back in here — you would be comparing the two blocks of recognised text somewhere else, with recognition errors showing up as differences that are not real.
Currently the tool compares exactly two PDFs at a time.
No. There is no text to compare in a scanned image, and OCR does not solve it for you here: it returns plain text rather than a PDF carrying a text layer, so there is no recognised document to load back in. If you compare the two transcripts elsewhere, expect OCR mistakes to show up as differences that are not really there.
Comparison is text-based. Changes to images, logos and signatures are not reliably detected, so check those visually.
No. Both files are processed in your browser, which matters given that document comparison usually involves contracts and other confidential material.
Reflowed text, different font embedding, or a document regenerated by different software can all produce differences that are not substantive edits. Focus on changed words and numbers.

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About Compare PDFs

Comparing two PDFs matters most in exactly the situation where mistakes are expensive: a contract comes back from the other side "with a couple of small changes". Reading both documents in full is slow and unreliable, and the human eye is very good at skipping over a changed number.

A comparison finds differences; it does not tell you which ones matter. A reformatted paragraph and an altered payment term both register as changes. The value is in guaranteeing that nothing is missed, after which judgement is still entirely yours.

One practical limit: comparison works on text. If one or both documents are scanned images, there is no text to compare, and this tool cannot get you past that. OCR PDF will read the scans, but it returns plain text rather than a PDF carrying a text layer, so there is nothing to load back in here. Comparing two recognised transcripts is a job for a text comparison tool, and OCR errors will show up in it as differences that are not real.

Tips and limits

  • Scanned documents have no text layer, and OCR does not give you one — it returns plain text, so there is no recognised PDF to compare here.
  • Step through differences one at a time. Scrolling and eyeballing defeats the point.
  • Formatting-only changes are flagged too — not every difference is substantive.
  • Compare the versions you actually sent and received, not your working copies.
  • For contracts, note the material changes outside the tool so you have a record.