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How to Compare Two PDF Files in Adobe Acrobat (Step-by-Step)
Adobe Acrobat Pro includes a dedicated Compare Files tool that finds every difference between two versions of a PDF and presents them in a filterable report. If you’re moving from DiffPDF to a supported professional tool, this is the workflow to learn. Here’s exactly how it works.
Quick answer: In Acrobat Pro, go to Tools > Compare Files, select the older PDF on the left and the newer PDF on the right, click Compare, then review the summary report and step through each change with Go to First Change. Use the filter to show only text, image, annotation, or formatting changes.
Before you start: the Compare Files tool requires Adobe Acrobat Pro (not the free Reader). A 7-day free trial is enough to compare a backlog of documents. Start your free trial →
Step 1: Open the Compare Files Tool
Launch Adobe Acrobat Pro (Mac or PC). In the top menu choose Tools > Compare Files, then click Open. You’ll see two file pickers: Old File on the left, New File on the right.
Step 2: Select the Two PDFs
Click Select File on the left and choose the older version; click Select File on the right and choose the newer version. If you mix them up, use the swap arrow between the two panes. Getting old/new the right way round matters — the report describes changes as insertions into the new file.
Step 3: Adjust the Settings (Optional but Recommended)
Click the gear icon before comparing. Here you can:
- Limit page ranges — compare only pages 1–20 of a 200-page document to save time.
- Compare text only — ignores layout shifts; ideal for long text-heavy documents.
- Choose content types — include or exclude headers/footers, graphics, formatting differences, backgrounds, and annotations.
- Scanned documents mode — better handling for scanned pages and drawings.
Step 4: Run the Comparison
Click the blue Compare button. Acrobat analyzes both files and opens the results in a new document. The first page is a summary: comparison timestamp, file info, total change count, and a breakdown of replaced, inserted, and deleted content.
Step 5: Review Each Change
Click Go to First Change to jump to the first difference, then use the next/previous controls to step through them all. Two view modes help:
- Side-by-side view — old file left, new file right, with a highlight band connecting each change across both.
- Single-page view — one file at a time with all changes highlighted in context.
Use the filter dropdown to show only the change types you care about — for example, text changes only, hiding formatting noise.
Tips for the Best Results
- OCR scanned PDFs first. Comparison works on text layers; run Acrobat’s OCR on scans before comparing.
- Use text-only mode for reflowed documents. If repagination shifted everything, appearance comparison drowns you in noise — text mode finds the real edits.
- Save the report. The comparison output is itself a PDF — keep it as your audit trail for contract reviews.
Limitations to Know
Compare Files is a Pro-only feature — the free Adobe Reader can only open two PDFs side by side for manual inspection. Very large documents (hundreds of pages with heavy graphics) can be slow; narrowing the page range helps. And like every automated diff, it flags differences, not importance — a human still decides what matters.
Try It on Your Own Documents
The 7-day free trial includes the full Compare Files tool — enough to work through a real review backlog.
Start Free TrialFrequently Asked Questions
Doing legal review? The Compare Files output above is exactly what lawyers call a legal blackline — here’s how the terminology works.
Can the free Adobe Reader compare PDFs?
No — Reader can open two PDFs side by side for manual comparison, but the automated Compare Files tool with change reports requires Acrobat Pro (a free trial is available).
Can Acrobat compare scanned PDFs?
Yes, with caveats. Run OCR first so the pages have a text layer, or enable the scanned-documents option in Compare settings. For a pure visual check, Appearance mode in a tool like DiffPDF also works.
How is Acrobat’s compare different from DiffPDF?
Acrobat produces a structured, filterable change report and handles annotations, headers/footers, and formatting as separate change types. DiffPDF (free) highlights differences visually but offers no formal report. DiffPDF is still fine for quick checks.
Last updated: October 2026. diffpdf.org is an independent resource center, not affiliated with Adobe or Qtrac Ltd.