What is it?
Compare PDF puts two versions of a document side by side and shows what changed. Words that were removed are struck through in red, new words are green, and a picture of each page marks changed areas in red, so you also notice moved logos, signatures and stamps.
Who is it for?
Tenants and landlords checking a revised rent agreement, buyers comparing a new quotation, lawyers and clerks reviewing drafts, students checking a corrected report, and anyone told “only small changes” who wants to see them all.
How to use it
- Choose The original copy (PDF A), then The newer or changed copy (PDF B).
- Tap Compare. It shows Comparing page … while it works.
- Read the text changes, then use ‹ Previous page and Next page › to look at Page with differences in red for each page.
Reading the results
- Red struck-through words were in the original but not in the new copy.
- Green words are new.
- Red areas on the page picture are visual changes: moved text, a changed logo, a new signature or stamp.
Worked example
Tap Try a sample: two versions of a short rent agreement are compared. The monthly rent changes and a line about pets is added; both stand out immediately. Always compare before you sign a “final” version that someone else edited.
Is my file uploaded?
No. The file is opened and changed inside your browser, on your own phone or computer. Nothing is sent to us, and closing the page clears it.
Errors and how to fix them
- “This PDF is password-protected. Remove the password first”: open it once with Remove PDF Password (you need the password), then use the unlocked copy here.
- Still opening the PDFs, one moment…: you tapped Compare while the files were loading. Wait a second and tap again.
- Everything shows as changed: one copy is a scan (a picture) and the other is text. Make the scan searchable first with Make Scanned PDF Searchable (OCR), or compare two scans using the red page pictures only.
- Pages are out of step: if a page was added near the start, every later page looks different in the pictures. The word list still shows the real changes.
Open the tool: Compare PDF
Still stuck?
Contact support. Tell us which tool or page you were using, what you tapped, what you saw, and your phone or computer and browser (for example: Android phone, Chrome). We reply by email.
Questions, or an error not listed here?
Tell us in the comments: what you were doing, the exact message you saw, and your device and browser. We read every comment and add new fixes to this article.