Compare two documents
Upload two files and get an equality matrix — bytes, content and metadata — so you can tell whether it is the same document and on which layer it differs.
How it works
- 1. Upload the original (A) and the new version (B).
- 2. We fingerprint both and compare each layer.
- 3. The matrix shows what is identical and what changed.
A — original / old
B — new
Without a layered compare
- One "compare" button can’t tell you why two files differ — the bytes, the text, or only the metadata.
- Adobe Acrobat's Compare is Pro-only and desktop-bound, and often marks the whole document as changed.
- Text-only diff tools break on scans, stamped pages and re-flowed layouts.
- You get a highlighted screen, not a record you can attach to a file as evidence.
With PDFengine Compare
- An equality matrix across four layers — bytes, text, visual and metadata — with a plain-language verdict.
- Online, nothing to install; works on scans without a text layer and even on .eml/.msg email trees.
- A separate visual pixel diff shows exactly where something moved, with a heatmap.
- Export the result as evidence — a PDF, PNG or JSON you can keep on file.
How it works
Upload two files
Upload the original (A) and the new version (B).
We compare each layer
We fingerprint both and compare each layer.
Read the verdict
The matrix shows what is identical and what changed.
When to compare two PDFs
From contract review to version control — pick the comparison that fits the question.
Contract & version review
Check whether a returned contract is the exact draft you approved, or find the single clause that changed between two versions.
Scanned & stamped documents
Compare scans that have no text layer with a pixel diff — signatures, stamps and layout shifts all included.
Evidence you can file
Export the equality matrix or the diff as PDF, PNG or JSON, so you can attach proof of what changed to your file.
Frequently asked questions
What's the difference between a content compare and a visual diff?
The content compare answers "is this the same document?" across bytes, text, visual and metadata. The visual diff answers "where did the pixels move?" with a page-by-page heatmap. For clean digital drafts the content compare is enough; for scans, stamps or layout shifts you want the visual diff.
Why does Adobe Acrobat mark the whole document as changed?
Usually because the text stream was re-flowed — often by a round trip through Word or a different PDF producer — so every character's position shifts and a text-first comparison sees everything as new. A pixel-based visual diff ignores the text stream and isolates the genuine edits.
Can I compare two scanned PDFs without a text layer?
Yes. Scans have no reliable text layer, so use the visual diff: it renders each page as an image and highlights where the pixels differ, with a "% changed" per page.
Can I compare email threads (.eml or .msg)?
Yes. Upload two email files and PDFengine compares them node by node, matching each attachment and flagging nodes added or removed between the two versions.
Is my file stored, and what does it cost?
Comparing is online, so the files are uploaded to run the comparison, then handled under our retention policy. The layered content compare is free to try; the visual diff is priced per paired page.
Need to see exactly where it changed?
Switch to the visual diff for a pixel-by-pixel heatmap of every page.