Redline Compare two PDFs.

See exactly what changed between two versions. Word-level redline — files never leave your browser.

📎 Merge ✂️ Split 🔄 Rotate 🗑️ Delete Pages ↕️ Reorder 🖼️ PDF to Image 📑 Image to PDF #️⃣ Page #s 💧 Watermark 📷 Extract Images 🔒 Protect 🔓 Unlock 📝 PDF to Word 📄 Word to PDF 🔴 Redline 🗜️ Compress ✍️ Sign PDF
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More PDF Tools

Everything you need to fix, edit, and manage your PDFs.

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Merge PDF

Combine multiple PDF files into one.

✂️

Split PDF

Extract specific pages from any PDF.

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Rotate PDF

Fix sideways or upside-down pages.

🗑️

Delete Pages

Remove unwanted pages from any PDF.

↕️

Reorder Pages

Change the page order of any PDF.

🖼️

PDF to Image

Convert PDF pages to PNG images.

📑

Image to PDF

Convert images into a PDF document.

#️⃣

Add Page Numbers

Add page numbers to every page.

💧

Add Watermark

Stamp text across every page.

📷

Extract Images

Pull all images out of a PDF.

🔴

Redline Compare

Compare two PDFs side by side.

🗜️

Compress PDF

Reduce your PDF file size.

🔒

Protect PDF

Add password protection.

🔓

Unlock PDF

Remove password protection.

📝

PDF to Word

Convert PDF to editable Word doc.

📄

Word to PDF

Convert Word docs to PDF.

✍️

Sign PDF

Add your signature to any PDF.

How to Compare Two PDFs with Redline Online for Free

Need to see exactly what changed between two versions of a document? Our redline comparison tool highlights every addition and deletion between two PDFs, just like Track Changes in Microsoft Word. Perfect for reviewing contract revisions, policy updates, and document edits.

How It Works

Upload the original PDF first, then the revised version. Our tool extracts the text from both, compares them word-by-word using a longest common subsequence algorithm, and generates a redlined version showing additions in green and deletions in red with strikethrough.

How FixMyPDF Is Different

Most online PDF tools — including iLovePDF, SmallPDF, and Adobe Acrobat online — upload your files to their servers for processing. That means your contracts, tax documents, medical records, and confidential business files pass through a third party's infrastructure. FixMyPDF.ai is different: every tool runs entirely in your web browser using client-side JavaScript. Your files are never uploaded, never stored on a server, and never accessible to anyone but you. There is no backend server processing your documents — it all happens on your device.

Frequently Asked Questions

Does it compare formatting or just text? Currently the tool compares text content only. Formatting changes like font or spacing are not highlighted.

Will it work on scanned documents? Only if the PDF contains extractable text. Scanned images without OCR won't produce meaningful comparisons.