Compare Two PDFs
Find what changed between two versions of a document — the redlined contract, the revised thesis, the updated policy — without reading both end to end.
- PDF · multiple files
- up to 25 MB per file
- Deleted after one hour
How it works
- 01
Upload two PDFs
Original first, revised version second — drag to swap if needed.
- 02
Compare
The text of each page is matched word by word.
- 03
Open the report
An HTML file that opens in any browser; unchanged pages are dimmed.
What Compare PDFs does
The second draft of a contract arrives with 'a few small changes'; the revised thesis chapter comes back from a supervisor; a supplier updates their terms. Reading both versions in full to find what moved is slow and unreliable. This tool extracts the text of each page from both PDFs, aligns them word by word, and writes a report in which removed words are struck through in red and added words are highlighted in green, page by page, with unchanged pages dimmed so the eye goes straight to the differences. The report is a single HTML file: open it in any browser, print it, or send it on. Upload the original first and the revision second so 'added' and 'removed' mean what you expect.
Limitations
- Text only. Layout, colour and image changes are not reported unless the words changed.
- Pages are compared by position; an inserted page shifts everything after it.
When you'd use it
- Checking what changed between two contract versions
- Reviewing a supplier's edits to your terms
- Confirming a re-issued invoice is identical apart from the date
Formats and limits
- Accepts
- .pdf — a password-protected PDF needs its password, or Unlock PDF first
- Produces
- HTML report
- Files per run
- Several — drag to set the order
- Size limit
- 25 MB per file
What happens to your file
Processed over an encrypted connection and deleted after one hour.
Full detail in the Privacy Policy.
Questions
Does it compare layout or images?
No — text only. A moved paragraph or a changed picture is not reported unless the words changed. That is the right tool for contracts and manuscripts; for design changes, export both to PNG and compare visually.
Which file should go first?
The older one. 'Removed' then means text that was in the original but not the revision, and 'added' the other way round. Drag the files to reorder them before running.
What if the documents have different page counts?
Pages are compared by position, and extra pages at the end appear as entirely added or removed. If a page was inserted in the middle, everything after it shifts — the report still shows the changes, just spread across pages.
Can it compare a scanned PDF?
Only after OCR PDF has given it a text layer. Comparison works on text; a scan has none until it is recognised.
Why does it report changes on a page where I see none?
Usually a formatting difference the eye ignores but the text does not: a hyphenation change, a re-flowed line, or a different character for a dash or quote mark. The report shows exactly which words differ, so these are quick to dismiss.
Does it detect a paragraph that was moved?
A moved paragraph appears as removed in one place and added in another. The words are identical, so both blocks are easy to spot and pair up.
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