How it works
The PDF Compare tool renders a selected page from two different PDFs side by side, letting you visually inspect differences between document versions — useful for proofreading revisions, reviewing contract redlines, comparing two versions of a technical spec, or verifying that an approved layout matches the printed output.
How to use it: upload PDF A (the original or reference document) and PDF B (the revised or comparison document). Both documents render their first page by default. Navigate to the specific page you want to compare using the page controls under each panel. The panels are independent — you can compare page 3 of document A with page 5 of document B.
What you can compare: - Visual layout changes: moved text blocks, changed headers, shifted margins - Content changes: added or removed paragraphs, replaced figures, updated tables - Formatting changes: font size differences, bold/italic changes, line spacing - Image differences: updated charts, replaced diagrams, watermark additions
What this tool does NOT do: it does not produce a tracked-changes view or automatically highlight differences — it shows each document page at full quality for manual visual comparison. For automated diff highlighting, specialized tools like diff-pdf or Adobe Acrobat's Compare Documents feature are required.
Rendering: each page is rendered at 1× scale using PDF.js at its native resolution. Pages are displayed in scrollable panels on large screens, stacked vertically on mobile.
Privacy: both PDFs are rendered in the browser using PDF.js. No content is uploaded.
Frequently Asked Questions
- No — the tool renders each PDF page at full quality for side-by-side visual inspection. Automated difference highlighting (pixel-level diff or text-level diff) is not implemented. For automated visual diffs, specialized tools like diff-pdf (command-line) or Adobe Acrobat's Compare Documents feature are appropriate. This tool is best for manual review where you can quickly scan both pages simultaneously.
- No. The left and right panels navigate independently. You can compare page 3 from a 5-page document with page 7 from a 20-page document. Each panel shows its own page count and has its own navigation arrows.
- You can upload the same file to both slots if needed, but this produces identical panels — not useful for comparison. The typical use case is uploading an original version to one slot and a revised version to the other, then navigating to the page where changes were made.
- Pages are rendered at 1× scale (the native PDF coordinate scale, which corresponds to 72 DPI on-screen). For a crisp rendering, you would need a higher scale factor, but that would significantly increase rendering time for large PDFs. For fine-text comparison, zoom in using the browser's native zoom (Ctrl+scroll or pinch) to enlarge both panels simultaneously.