Compare PDF Documents — Highlight Text Changes Side by Side

Compare two PDFs locally, review changed words and download either document with red highlights. Selectable text, no uploads.

Compare PDF documents side by side and find text differences between two local versions. Choose an original PDF and a revised PDF to highlight removed words in the original and added words in the revision. This PDF diff tool compares selectable text and lets you download either document with permanent red marks. Use it to review wording in revised reports, letters or other text-based PDFs. 📂 Load the original and the revision Select a file in each of the Original PDF and Changed PDF areas, or drop a PDF into each area. Once both are loaded, choose Compare PDFs. Change PDF replaces one selected document. Change files clears the pair for a new comparison. Progress is shown while files are processed, and Cancel stops active work. 🔍 Compare pages or extracted text Use Pages to see the original page appearance with changed words marked on each side. Switch to Text to inspect the extracted text side by side. The page selector shows comparison status, and Previous and Next let you move through the results. Highlight changes can hide the preview overlay temporarily without discarding the comparison. 📝 What counts as a difference Pages are paired by page number and text follows embedded extraction order. Spaces and line breaks are normalized. Adding a whole page can shift later comparisons, and moving content can change alignment. The tool does not infer document meaning or automatically match equivalent sections across different page arrangements. Illustrations, font styling and page layout are outside the detected text changes. 📥 Download highlighted PDFs Each document has its own Download control. Export adds visible red vector marks while retaining source pages and selectable text. Download the marked original to show removed wording or the marked revision to show additions. These marks do not remove the underlying text and are not redaction. Adding them does not preserve the validity of a digital signature. 📄 Use PDFs with selectable text Scans without a text layer are labeled explicitly. Their page images can be viewed, but they receive no text-change marks because the extension does not perform OCR. Unusual fonts, ligatures and mixed-direction text can make highlight edges approximate. Review the marks alongside the visible pages when precise placement matters. 💻 Capacity and local handling Each PDF can be up to 40 MiB and 100 pages. Unlock password-protected files before selecting them. Text is limited to 100,000 characters per page and two million per comparison. Exceptionally large or complex differences can receive an error. A failed text comparison disables marked downloads until a successful retry; a preview failure may still leave text results and export available. Documents stay in memory until replaced or the tab closes. There is no upload service, account or stored document history.