How do I compare two PDF files online?

Drop the original PDF into the left panel and the revised PDF into the right panel. Zolkit extracts available text in the browser and highlights removed, added, and changed lines side by side.

Why is text missing from my PDF diff?

Some PDFs are scanned images, encrypted, or contain text as paths instead of selectable characters. If text is missing, run OCR on the PDF first and paste the OCR text into the two comparison panels.

Is PDF comparison private?

Zolkit's PDF comparison runs in the browser and does not require uploading the document. The privacy model is local-first because parsing and diffing happen on your device.

Can this compare PDF layout changes?

This tool compares extracted text, not pixel layout. For visual layout differences, an image or pixel diff workflow is a better fit.

Compare PDF Documents

Compare two PDF documents online and review text differences side by side. Browser PDF text extraction with no upload required.

For scanned PDFs or image-only files, copy the OCR text into the comparison panels before comparing.

Ignore whitespace

Original

Changed

Comparison results

Added: 0Removed: 0Changed: 0Unchanged: 0

Add content on both sides to compare.

PDF comparison is common for contracts, proposals, reports, invoices, and policy documents where a small edit can matter. This page opens Zolkit's diff checker with a PDF-focused workflow: drop the earlier PDF on the left, drop the revised PDF on the right, then review extracted text differences in red and green. PDF text extraction runs in the browser and works best for digital PDFs that contain selectable text. Scanned PDFs, flattened image PDFs, and encrypted files may still need OCR first. Because the comparison runs locally, it is useful for reviewing confidential business or legal documents without sending them to a server.

Related Comparison Pages

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Online Diff Checker for Text, JSON, and Documents

Zolkit's Diff Checker compares two texts, code snippets, JSON payloads, Word files, Excel sheets, PowerPoint decks, and PDF documents in your browser. Use it to spot added, deleted, and changed lines without uploading sensitive contracts, drafts, API responses, or internal documents.

Browser-Only Privacy

Text comparison and supported document extraction run locally in your browser, so confidential drafts and legal files do not need to be uploaded.

Document Input

Drop DOCX, XLSX, PPTX, TXT, CSV, JSON, and PDF files, or paste text directly into the side-by-side panels.

JSON Diff Mode

Normalize JSON before comparing so formatting noise is removed and structural changes are easier to review.

Side-by-Side Results

Added lines are highlighted in green, removed lines in red, and changed rows are aligned for fast review.

Whitespace Control

Ignore whitespace when indentation or line wrapping should not count as a meaningful change.

Free to Use

Compare text and files without an account, installation, or per-document limit from Zolkit.

How to Compare Text or Documents

1
Paste text into both panels, or drop one supported file into each side.
2
Choose Text or JSON mode, then enable Normalize JSON or Ignore whitespace when useful.
3
Review the side-by-side diff where additions are green, removals are red, and changed rows are aligned.