PDF Scroll Sync Tool
Open two PDF files side by side, synchronize scrolling of both document windows, and quickly compare document differences locally in your browser.
Select Your Language to Launch the Tool
Key Functions
Side-by-Side View
Compare two PDF documents side by side in a single viewport. Easily detect additions, deletions, or structural modifications instantly.
Offset Alignment
Perfect for asymmetric documents. Keep custom initial scroll differences, and the secondary window follows by the exact same distance (delta).
Absolute Alignment
Locks vertical scroll percentages. Both documents scroll together at identical relative positions—ideal for comparing draft revisions.
Instant Layout Swapping
Swap left and right document positions using pure CSS Flexbox orders instantly. Keeps file info, details, and buttons where they belong.
Text Selection & Copy
Renders an invisible text layer over the rendered PDF canvas. Highlight and copy text directly from the comparing documents seamlessly.
Flexible Zoom Controls
Configure independent zoom scales, including "Fit Width" and absolute percentages. Saves all mode configurations and settings locally.
Common Use Cases
Bilingual Reading & Translation
Open the original foreign language PDF on the left and the translated document on the right. Synchronous scrolling lets you read cross-referencing translations effortlessly.
Contract & Agreement Proofreading
Compare bid drafts or revisions side by side. Use Absolute Alignment to spot minor deletions, typos, or unauthorized edits immediately.
Academic & Literature Review
Cross-reference draft revisions against reviewer feedback sheets, keeping related sections aligned via Offset Scroll Mode.
Format Conversion Consistency
Check if conversion from Word/Markdown to PDF has displaced images, disrupted formatting, or caused word wrapping bugs across multiple pages.