PDF Compare | Check Differences Between PDFs
Compare two PDFs with semantic word-level diff, visual pixel overlay, and off-thread processing via Web Workers. Zero uploads, entirely local.
Original PDF (A)
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Original / Baseline file
Revised PDF (B)
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Revised / Updated file
How It Works
Upload Original (A) and Revised (B) PDFs
Your PDF is analyzed in the background so the page stays fast and responsive.
The tool detects small edits (like typos) and larger text changes between documents.
Visual mode highlights page differences so you can quickly spot what changed.
Privacy & Local Processing
Our PDF Compare tool runs entirely in your browser. Text extraction and diffing happen in a Web Worker a separate background thread so neither the UI nor your data ever leaves your device. Visual mode renders pages to off-screen canvases and pixel diffs them locally. Nothing is ever uploaded to a server.
Note on accuracy: Text diff compares extracted content only formatting changes (font, size, colour) appear only in Visual mode. Scanned PDFs may produce incomplete text. The semantic classifier uses Levenshtein edit distance relative to word length to distinguish small typo corrections from full rewrites.