How to Compare Two PDF Files Online Free
Reviewing a contract revision or checking if a supplier changed something in the latest PDF version? PDF Boss compares two PDF documents and highlights every addition, deletion, and change — free, no sign-up.
How to Compare Two PDF Files in 3 Steps
Step 1 — Go to pdfboss.in/compare-pdf
Step 2 — Upload the original PDF and the revised PDF
Step 3 — Click Compare to view a highlighted diff report
Added text is shown in green, deleted text in red, and the comparison report can be downloaded as a PDF.
When PDF Comparison Saves You Time
- Legal contracts — Verify what changed between contract versions sent by counterparty
- Financial reports — Check if a supplier modified their quotation before resubmitting
- Regulatory submissions — Confirm that only intended sections were updated in revised documents
- Academic papers — Review what a co-author changed in the latest draft
- Policy documents — Identify exactly which clauses were updated in the new version
Understanding the Comparison Output
The comparison report shows:
- Added text — New words or sentences in the revised version (green highlight)
- Deleted text — Words present in the original but removed from the revision (red strikethrough)
- Changed text — Words that were replaced (shown as a deletion + addition pair)
- Page-level changes — If entire pages were added or removed between versions
The report is exported as an annotated PDF for easy sharing with colleagues.
Try Compare PDF Free →Frequently Asked Questions
Does the comparison highlight specific changed words?
Yes. Added text is highlighted in green, deleted text in red, and moved content is indicated separately.
Can I compare scanned PDFs?
Scanned PDFs must be OCR-processed first to have a text layer. Run OCR on both files before comparing.
Is there a page limit for comparison?
Free users can compare PDFs up to 25 MB each. Large documents are compared page by page.