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Compare PDF Online Free — PrivaTools

TL;DR: Upload two PDFs and download a side-by-side visual diff with differences highlighted — or get a text-only diff report.

Compare two PDFs online for free — upload two versions of a document and get a visual diff highlighting every text change, addition, and deletion. Essential for contract review.

Compare PDF is free because the whole 214-tool PrivaTools project is open source, not ad-supported. No trackers load in your browser, no account is created, and files are deleted immediately after processing — self-host it if you want the guarantees on your own hardware.

What Compare PDF is best for

Compare two PDFs online for free — upload two versions of a document and get a visual diff highlighting every text change, addition, and deletion. Essential for contract review. Use it when you need a quick, private, no-account way to handle a pdf in the browser, or when you want an auditable open-source alternative to iLovePDF, Smallpdf, Adobe Acrobat, PDF24, and Sejda. The page at /tool/compare-pdf is designed for one clear job: upload or provide the input, choose only the options that matter, and download the result without creating an account or passing through a sales funnel.

Privacy model for Compare PDF

PDF operations that need server-side libraries run inside the PrivaTools container and return a fresh download; browser-only PDF helpers stay on-device. Temporary input and output files are not used for analytics, model training, advertising profiles, or product telemetry. The public demo uses anonymous page-view analytics only; file bytes, extracted text, filenames, passwords, signatures, and generated results are outside that analytics path. If your organization needs stricter controls, you can self-host all 214 PrivaTools utilities and keep processing on your own infrastructure.

Quality checklist

Before running Compare PDF, confirm that the source file opens correctly and that you have permission to process it. Keep an untouched original, run one operation at a time when quality matters, and use Pipeline when you want repeatable multi-step output. For sensitive material, review the downloaded result before sharing it. For large files, give the browser time to finish the download and avoid refreshing the page mid-run. If a password, damaged upload, unsupported codec, or malformed document blocks processing, PrivaTools returns a plain-language error so you can pick the next recovery step instead of guessing.

Operational details

Compare PDF is intentionally narrow: it does one pdf task and hands the result back as a normal download. That makes the output easy to inspect, rename, archive, attach to email, or feed into another tool. If you need a repeatable workflow, save the page, bookmark a Pipeline recipe, or self-host the API so the same steps can run from internal scripts. The interface avoids accounts and cloud folders on purpose: the safest default for private files is to process only the current request, return the result, and leave long-term storage under your control.

Using Compare PDF on any device

Compare PDF runs in any modern browser on Windows, macOS, Linux, Android, and iOS — there is nothing to install, no extension to add, and no desktop app to keep updated. Because the interface is a single page, you can bookmark it, send the link to a colleague, or open it on a phone and get the same result you would on a laptop. There are no watermarks stamped onto your output, no sign-in wall before the download, and no paid tier that unlocks the “real” version later — the Compare PDF you see is the complete tool. For teams that would rather keep everything in-house, the same endpoint ships in the MIT-licensed, self-hostable build, so you can run it behind your own firewall with identical behaviour and no outbound calls. That combination — instant in the browser for individuals, fully self-hostable for organizations — is what keeps a private file genuinely private from upload to download.

How to use the Compare PDF tool on PrivaTools

  1. Upload two PDFs — The first is the baseline; the second is the revised version.
  2. Choose comparison mode — Text: word-level diff. Visual: side-by-side rendered pages with changes highlighted.
  3. Download or view the diff — PrivaTools returns a report PDF with additions in green and deletions in red, plus a summary of changed pages and word counts.

Frequently Asked Questions

Does this work on scanned PDFs?

Only with OCR. Run OCR PDF on both files first so the text layer is present, then compare.

How accurate is the text diff?

Word-level diff handles reordering, insertion, deletion, and formatting changes. Diffs based on character runs would be noisier.

Can I compare more than two files?

Run Compare twice (A vs B, then B vs C) to chain a multi-revision comparison.

Last reviewed 2026-05-01 by the PrivaTools maintainers. Source code on (MIT-licensed, self-hostable).

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