Compare Two PDF Files Online

Spot every text change between two PDF versions in seconds. Side-by-side view, automatic difference highlighting — free and 100% in your browser.

Document A

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Maximum file size: 10MB

Document B

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Maximum file size: 10MB

Comparing two versions of a PDF is the kind of task that used to require expensive desktop software like Adobe Acrobat Pro or specialized legal-redlining tools. Dokfo's free PDF compare tool brings the same capability to your browser: upload version A, upload version B, and instantly see a side-by-side view with every textual addition, deletion, and modification highlighted automatically. This is the workflow lawyers use when negotiating contract revisions, what writers use when editors return a manuscript with tracked changes flattened, and what auditors use to spot subtle wording shifts between two policy drafts. Instead of squinting at two PDFs in separate windows trying to find what's different, you get a single view that points right to the changes. Dokfo's compare engine works best with text-based PDFs — documents originally exported from Word, Google Docs, LaTeX, or any modern editor. For scanned PDFs, run OCR first using Dokfo's OCR PDF tool so the text becomes selectable, then compare the OCR'd versions.

How to Compare Two PDFs — Step by Step

1

Upload the original PDF (version A) by clicking or dragging it onto the first upload area. Dokfo loads it locally and prepares it for comparison.

2

Upload the revised PDF (version B) into the second area. Both files are read in your browser — neither is sent to a server.

3

Click "Compare" to see a side-by-side view with additions, deletions, and changes highlighted in color. Scroll through to review every difference.

Why Compare PDFs With Dokfo?

Side-by-Side Visual Diff

See both versions on screen at once with changes highlighted in line. No need to mentally cross-reference between two windows or print copies side by side.

Automatic Change Detection

Dokfo's diff engine identifies inserted text, deleted text, and modified passages automatically. You don't need to know in advance where to look.

Browser-Based Privacy

Both PDFs are processed locally. Confidential contracts, drafts under negotiation, or unreleased reports never leave your device — critical for legal and corporate use.

No Sign-Up, No Limits

Compare as many document pairs as you need without creating an account. There's no daily cap, no email signup wall, and no software to install.

When to Compare PDFs

Spot edits in contracts, NDAs, and legal agreements before signing — catch every word that changed during negotiation.
Verify that an exported document matches its source — useful when sending a final report to a client or regulator.
Find differences between policy versions, employee handbooks, or corporate procedures across revisions.
Compare drafts of academic papers, books, or technical documentation to track editor or co-author changes.
Audit accounting reports, financial statements, or compliance documents between fiscal periods.

Both Files Stay on Your Device

Dokfo's compare tool runs entirely in your browser. Both PDFs are read into memory, parsed locally with PDF.js, and diffed using a JavaScript text-comparison algorithm. Nothing is uploaded — which is essential when comparing confidential drafts, contracts under negotiation, or unreleased financial reports. You can verify privacy by opening Developer Tools → Network tab during comparison: no PDF content is transmitted.

Related PDF Tools

Merge PDF PDF to Word Edit PDF OCR PDF

Frequently Asked Questions About Comparing PDFs

How does PDF comparison work?

Dokfo extracts the text from both PDFs locally, then uses a diff algorithm (similar to what Git uses for code) to identify added, removed, and changed text. Results are shown side by side with color-coded highlights so you can spot every difference at a glance.

Can I compare scanned PDFs?

Comparison works best with text-based PDFs (those exported from Word, Google Docs, etc.). For scanned PDFs, first use Dokfo's OCR PDF tool to add a searchable text layer, then compare the OCR'd versions.

Will it detect formatting or layout changes?

The compare tool focuses on textual content — additions, deletions, and modifications. Pure formatting changes (font color, line spacing) without text changes may not be flagged. For a visual layout diff, view both PDFs side by side manually.

How many pages can I compare?

There is no fixed limit. Document pairs of hundreds of pages compare in seconds on a modern device. Very large documents may take longer depending on your machine.

Are my files uploaded?

No. Both PDFs are processed in your browser. Inspect the Network tab in Developer Tools during comparison to confirm — no document content is transmitted.

Can I export the comparison report?

You can save the side-by-side view by printing the page to PDF using your browser's Print → Save as PDF feature. A native diff-export feature is on our roadmap.

What if my PDFs are password-protected?

Remove the password first with Dokfo's Unlock PDF tool (assuming you have the password), then compare the unlocked versions.

Is the comparison legally admissible?

Dokfo's compare tool is for review and reference. For legal redlining or audit-grade comparisons that may be entered as evidence, work with your legal team and use formally certified tooling.