Diff MasterPDF COMPARISON GUIDE
How to compare two PDF files online for free
Use the free online PDF Compare tool when you need a text or visual diff. Choose Text differences for wording; choose Visual differences for layout, fonts, images or scanned-page appearance.
- Select Text differences or Visual differences before choosing the files.
- Add the original PDF and the changed PDF; the free comparison processes them privately in the browser.
- Review each changed, added or removed page using the selected mode.
Choose the mode that answers your question
| Use this mode | When you need to know | What it does not prove |
|---|---|---|
| Text differences | Whether extractable wording was added, removed or modified. | Layout, font, image or visual equivalence. |
| Visual differences | Whether rendered page pixels, layout, fonts or images changed. | Semantic, legal or wording equivalence. |
Three steps to compare PDFs online for free
- Open PDF Compare and select Text differences or Visual differences.
- Choose the original and changed file. Each PDF can be up to 50 MB and 150 pages in the current version.
- Select Compare PDFs, follow page-level progress, then navigate every page reported as changed, added or removed.
How to compare two PDFs without Acrobat
If you usually use Acrobat to compare PDFs, select the original and changed files in PDF Compare instead. Text differences is useful when the review is about wording; Visual differences is useful when the review is about page appearance. Both modes run in this browser tab without an Acrobat license, installation or file upload.
How to choose PDF comparison software
There is no single best PDF comparison software for every review. Choose a text comparison when you need to find extractable wording changes, and choose a visual comparison when layout, fonts or images matter. Check the privacy boundary and the handling of scanned PDFs before using any tool with sensitive documents.
What happens with scanned PDFs?
A scanned page is often an image without extractable text. Text differences can therefore report that page as unavailable. Use Visual differences to compare the rendered page appearance. Diff Master does not perform OCR in the current version.
Why visual comparison can show extra noise
Font substitution, antialiasing, browser rendering and small layout shifts can change pixels even when wording looks similar. Review the highlighted regions and the original and changed page crops before deciding whether a visual change is meaningful.
Different page counts and page alignment
Pages are matched by page number. A page available only in the changed file is added; a page available only in the original file is removed. Diff Master does not automatically infer that later pages should be renumbered after an insertion.
Privacy and current limits
PDF bytes, extracted text, rendered pages and results stay in this browser tab and are not uploaded for comparison. Large or image-heavy PDFs can use significant browser memory. The tool does not provide OCR, signature validation, form semantics, legal conclusions or print colour certification.
Ready to compare?
Open the matching tool and keep both versions in this browser.
Open PDF Compare