PDF Diff
Compare Two PDF Files Online
Compare two PDF files online and see every difference in seconds. Six viewing modes cover every kind of comparison. Rich text for in-place changes, plain text for word-level edits, redline for legal review, image for visual layout checks, OCR for scanned PDFs, and details for file-level facts. Switch between them any time without re-uploading.
Every PDF-to-PDF comparison runs in your browser, so contracts, legal filings, and medical records stay private on your own device. Password-protected PDFs are unlocked on your machine and cleared the moment you close the tab. The redline export saves as one clean PDF with new wording underlined in blue and removed wording crossed out in red, ready to share with counsel or a counterparty.
Six Ways To Compare PDF Files
Different PDF files and PDF documents ask different questions. Pick the view that matches what you want to find out, and switch between them any time without re-uploading.
Rich Text
See changes right on top of the real PDF pages. Removed text in red, new text in green. The easiest mode when you just want to know what changed.
Plain Text
Just the words from both PDFs, in two clean columns, with differences highlighted word by word. Perfect when only the wording matters.
Redline
The classic legal redline. New wording underlined in blue, removed wording crossed out in red. One clean document, ready to send to a reviewer.
Image
Compares both PDFs page by page as pictures. Catches moved logos, shifted margins, or anything else the eye can see but text can miss.
OCR
Reads text out of scanned PDFs and image-only documents, then compares it like any other file. Built for files you can't select text in.
Details
A quick look at both files side by side. Page count, size, author, dates, encryption. Handy as a first check before digging in.
Legal Redline Comparison For Contracts
Redline mode produces the markup every lawyer, paralegal, and contract reviewer already knows. New wording is underlined in blue. Removed wording is crossed out in red. All in one clean document, ready to send to counsel or a counterparty.
Drop in two versions of a contract, NDA, or policy, and the redline comes back formatted and ready to share. Opens in any PDF reader, with no extra software needed on the other end.
What The Redline Export Includes
- One clean PDF with every new line in blue and every removed line crossed out in red
- A summary at the top showing how many insertions, deletions, and edits were found
- Line numbers from the original so reviewers can point to exact spots
- Opens in any PDF reader, on any device, with nothing else to install
Password-Protected PDF Comparison
Contracts and legal PDFs often come locked with a password. This PDF to PDF comparison works on encrypted files the same way it works on any other document. Drop them in, type the password when asked, and the comparison starts right away.
The password stays on your device and is used only to open the file. Close the tab and it's gone. Nothing about the file or the password is sent anywhere.
- Spots password-protected PDFs the moment you upload them
- Asks for the password in the browser and keeps it on your device
- Every comparison mode works once the file is unlocked
- Handles two files with different passwords in the same comparison
This PDF is password protected. Enter the password to open it.
Try it yourself - upload a password-protected PDF above
How To Compare Two PDF Files Online
Four simple steps to compare two PDF files online. No sign-up, no downloads, no waiting.
Upload Your Original PDF
Drag your first PDF onto the left panel, or click to pick it from your files. It loads right in your browser.
Upload The Changed PDF
Drop the newer version on the right. Both files load at the same time and are ready to compare in seconds.
Pick A Comparison Mode
Switch between Rich Text, Plain Text, Redline, Image, OCR, and Details at the top. Your PDFs stay loaded the whole time.
Download The Result
Save the comparison as a new PDF to share with a colleague or reviewer. The redline export is ready to hand to counsel.
Why Pick This Free PDF Compare Tool
Free, private, and built around the questions people actually ask when comparing two PDF documents.
Fast Comparison
Most comparisons finish in seconds, even for long PDFs. No queue, no upload wait.
Your Files Stay Private
Comparisons run on your device. PDFs are never uploaded or stored anywhere. Safe for contracts, medical records, and financial documents.
See Changes Visually
Differences shown in colour right on the real PDF pages. Red for removed, green for added, yellow for edits. The visual language reviewers already know.
Six Comparison Modes
A redline for legal work, an image view for design-heavy PDFs, OCR for scans, and plain text when only the wording matters. Every kind of PDF gets the right view.
Legal Redline Export
The redline saves as a clean PDF with new text in blue and removed text in red. Share it with counsel or a counterparty with no extra formatting.
Works Without Internet
Once the page has loaded, you can turn the wifi off and keep comparing. Useful on flights and in secure offices.
Download As A PDF
Save any comparison as a new PDF. Rich text, image, and redline exports all save cleanly, ready to email or archive.
Works Everywhere
Runs in any modern browser, on a laptop or a phone. Nothing to install.
No Sign-Up
Open the page, drop in two PDFs, and compare. No email, no account, no credit card. Free for personal and business use.
What You Can Compare: PDF Documents, Contracts, And More
Any PDF you've got. Text-based, scanned, or password-protected. Here's where PDF-to-PDF comparison tends to come in handy most.
Legal And Contracts
Contract negotiations, NDA revisions, and regulatory filings. The redline mode is the one legal reviewers already expect, and OCR picks up scanned contracts from older archives.
- Comparing two versions of a contract during negotiation
- Reviewing NDA and master agreement changes
- Checking updates to privacy policies and terms of service
- Auditing regulatory filing revisions
- Going through merger and due-diligence documents
Reports And Design
Financial reports, brochures, design proofs, and marketing materials. Image mode catches layout shifts that a text comparison would miss.
- Reviewing design proofs between rounds
- Catching layout and formatting changes
- Auditing brochure and flyer revisions
- Comparing architectural and engineering drawings
- Comparing financial reports quarter over quarter
Technical And Academic
Technical specs, academic papers, user manuals, and research documents. Plain text and OCR pull the wording out of the formatting so you can focus on the content.
- Reviewing engineering change orders and design specs
- Tracking academic paper revisions
- Reviewing technical specification updates
- Comparing user manuals between releases
- Going through research paper peer-review changes
Frequently Asked Questions
What is a PDF diff tool?
PDF diff (also known as PDF compare) shows what changed between two PDF documents. Added text, removed text, and edits are all highlighted in colour, so you can see at a glance how one version differs from the other.
How do I compare PDF documents for changes?
Drag your original PDF into the left panel and the changed version into the right panel. The tool reads both files, lines up the pages, and highlights every difference. Switch between Rich Text, Plain Text, Redline, Image, OCR, and Details at the top to pick the view that fits what you're looking for.
Is this free PDF compare tool really free?
Yes. Free for personal and business use, with no sign-up, no daily limit, and no paid upgrade. Compare as many PDFs as you need.
Is my data safe when I compare PDFs here?
Yes. Comparisons run on your own device, right in the browser. PDFs aren't uploaded, stored, or sent anywhere. If a file has a password, the password is used only to open it and is cleared the moment you close the tab.
Can I compare password-protected PDFs?
Yes. When you upload an encrypted PDF, the tool asks for the password, unlocks the file on your device, and the comparison runs normally. You can even compare two files with different passwords in the same session.
Can I compare two PDF documents for differences?
Yes. Drop your original PDF on the left and the revised version on the right, and the comparison runs automatically. Every difference is highlighted in colour, with a choice of six views to fit the kind of review you're doing.
Can I use this on a Mac?
Yes. It runs in any modern browser on Mac, Windows, Linux, iOS, and Android. Nothing to install, nothing to download.
How does the redline view work?
Redline gives you a single document with new wording underlined in blue and removed wording crossed out in red. The same format lawyers and contract reviewers have always used, ready to share with counsel or a counterparty. Export it as a PDF and it opens in any reader.
Can I see visual differences between two PDFs?
Yes. Image mode compares the pages pixel by pixel, with five views to choose from. Highlight marks every changed area, Side by Side shows the pages next to each other, Fade blends them with a slider, Slide reveals one beneath the other, and Subtract shows only the pixels that differ.
Does the OCR really work on scans?
Yes. OCR reads the text out of scanned or image-based PDFs and compares it like any other document. Results depend on how clear the scan is, but most real-world scans work well.
Can I save the PDF comparison?
Yes. Rich Text saves as a new PDF with the coloured overlay on the original pages. Image saves the visual comparison. Redline saves a standalone marked-up PDF, ready to hand to a reviewer.
Does it work without internet?
Yes. After the page has loaded, you can disconnect and keep comparing PDFs. Everything runs on your own device.
Start Comparing PDFs - Free
Scroll up and upload your PDF files. No sign-up, no downloads, no limits.