Compare PDF
Spot text differences between two PDFs.
How to use Compare PDF
- 01
Upload the original PDF
Add the first version of the document — the baseline you want to compare against.
- 02
Upload the revised PDF
Add the second version — the draft, revision, or updated copy you want to check for changes.
- 03
Review the differences
The tool highlights added text in green and removed text in red, page by page, so you can spot every change at a glance.
Tested and last verified on
About Compare PDF
Upload two PDFs and get a clear, color-coded view of exactly what text was added or removed between them — perfect for contract and revision reviews. Runs entirely in-browser.
Finding exactly what changed between two versions
Contracts go through multiple rounds of review. Policies are updated and reissued. Academic papers are revised before resubmission. In each case, someone needs to know exactly what changed between the old version and the new one — not a vague sense of 'it looks different', but a precise, highlighted list of every added, removed, and modified word. Reading both versions side by side and trying to spot differences manually is slow, error-prone, and unreliable on long documents.
This tool automates the comparison. You upload both PDFs, and the tool extracts the text from each, runs a diff algorithm, and presents the results with colour-coded highlights: green for added text, red for removed text. You can walk through the changes page by page and know with certainty that nothing was missed.
How the comparison works
The tool extracts the text layer from both PDFs — the actual character data stored in each document — and runs a word-level diff algorithm to identify insertions, deletions, and changes. The results are presented inline: original text that was removed is shown in red, and new text that was added is shown in green. Unchanged text provides context around each change.
Because the comparison is text-based, it catches every word-level change, including subtle ones like a changed number, a swapped name, or a deleted clause. It does not flag visual-only changes (different margins, a moved image, a font change) that do not alter the text content. For those, a visual overlay comparison tool is needed.
Who uses this and practical advice
Lawyers compare contract drafts to verify that opposing counsel made only the agreed changes and nothing else was slipped in. Compliance teams compare policy versions to identify exactly what was updated. Editors compare manuscript revisions to review an author's changes. Procurement teams compare vendor proposals to see where terms differ.
For the most meaningful comparison, use documents that have a text layer — digitally created PDFs, not scanned images. If both documents are scans, run OCR on each first to create a text layer, then compare. And remember that the comparison is word-level: formatting changes, page layout shifts, and image swaps are not flagged. If you need to catch those, take screenshots of both versions and compare visually.
Questions
Everything runs in your browser. How we keep files private
Does it compare text or visual appearance?
It compares the text content of both documents. Added text is highlighted in green; removed text is highlighted in red. Visual-only changes (like a shifted image or a different font size) that do not alter the text are not flagged.
Can it compare very long documents?
Yes. The tool compares every page of both documents. Long documents take a bit more time to process, but there is no page-count limit.
What if the page count is different?
The tool aligns pages by their position in the document. If the revised version has more or fewer pages, the extra pages are shown as entirely added or removed.
Is the comparison done locally?
Yes. Both PDFs are processed entirely in your browser. Neither document is uploaded to any server — essential when comparing contracts, legal filings, or confidential documents.