Online document comparison

Compare two documents online

Upload an older and newer PDF or Word file. DocDiffAI finds the wording that changed, flags what may matter, and links every finding to the source page.

How should we compare these documents?

Revision reviewFind every wording change between an older and newer version. Key differencesSurface important differences, omissions, and contradictions between related documents.

Key Differences is source-cited and intentionally focuses on what matters; it is not an exhaustive redline.

Older document

Click or drop a file

PDF or Word up to 50 MB

Newer document

Click or drop a file

PDF or Word up to 50 MB

Before you upload

PDF or Word (.docx) · 50 MB per file · 600 combined pages maximum. The free diff and one-time AI Review are available for pairs up to 100 combined pages. Uploaded documents are scheduled for permanent deletion after three days unless you purchase an AI Review or choose Pro.

Encrypted in transit, stored privately, and yours to delete at any time.

Compare free, then choose whether you want AI review

Upload older and newer

Choose two versions of the same document, or close drafts you need to reconcile.

See every wording change free

Review additions, deletions, and revised language with source-page links.

Add AI Review if useful

For $9, prioritize changes that may affect cost, time, obligations, rights, or risk.

Industry statistics

Public construction, insurance, and legal counts, with a source on each line, live on our statistics pages. See construction statistics, insurance statistics, and legal industry statistics.

Common questions

Straight answers before you upload

Do I need an account?

No. Upload two files and keep the comparison page open. Add an email only if you want a backup link. Create an account later if you want saved comparisons and billing.

Which files can I compare?

PDF and Word (.docx), up to 50 MB each and 600 combined pages. Searchable text works best; scanned PDFs and complex tables may take longer.

How is this different from Track Changes?

DocDiffAI compares the content of two finished files, even when revision history is missing or the versions are PDFs. The free diff lists detected wording changes with source-page citations. A paid AI Review prioritizes what may matter.

How accurate is the comparison?

Every published finding points to quoted source language and a page you can check. If the evidence cannot be verified, DocDiffAI holds the report instead of presenting incomplete findings. Review the cited text before acting; DocDiffAI is decision support, not legal advice.

How long does a comparison take?

Processing starts automatically, and your free diff appears on the comparison page when it is ready. If you add an email, we also send a backup link. Long documents, scanned pages, and complex tables can take longer than a typical comparison.

What happens to my files?

Files are encrypted in transit and stored privately. Unpaid uploads are scheduled for permanent deletion after three days. Paid reports and source files remain available for up to three years unless you delete them sooner. Read the Privacy Policy.

Are my documents used to train AI?

Free comparisons may be used to evaluate and improve DocDiffAI. Paid content is not used for product-training datasets without your separate permission. Read the Privacy Policy.

What does it cost?

The deterministic wording diff is free for document pairs up to 100 combined pages. An AI Review is $9 for up to 100 combined pages and does not include chat. Pro is $39 per month for 10 AI Reviews, cited chat, and up to 600 combined pages per pair. Every paid purchase includes a 30-day money-back guarantee.