How to compare two PDFs with OnyxPDF
- Drop the first (original) PDF into the tool.
- Drop the second (revised) PDF.
- Click “Compare”.
- Read the side-by-side style diff: additions, removals and unchanged lines, plus the similarity stats.
Why do it in your browser instead of uploading?
- No upload — comparing two versions of a contract should not mean sending both to a server.
- Free — iLovePDF locks Compare behind Premium.
- Line-level diff with counts, so you can see at a glance whether a “small edit” was actually small.
- Works on any text-based PDFs: drafts, agreements, statements.
Good to know (honest limits)
- The diff is text-based: layout changes, moved images or restyled formatting are not compared. Two pages with identical text in different positions count as identical.
- Scanned PDFs have no text to compare — OCR both files first if you need their content diffed.
Frequently asked questions
What exactly is compared?
The extracted text of both documents, line by line. The output shows added lines, removed lines and unchanged lines, with counts and a similarity percentage.
Can it compare scanned documents?
Not directly — scans are images. Run each through the OCR tool first, then compare the extracted text.
Does it show formatting differences?
No. Font, layout and image changes are invisible to a text diff; it answers “what do the words say differently”, which is the question that matters for drafts and contracts.
Are both files kept private?
Yes. Both are read locally in your browser; nothing is uploaded or stored.