⚡ 10-second version
Someone sent back "the same contract with a couple of small changes." Drop both versions into tooladda.online/compare-pdfs.html and see exactly what moved, what was added, and what quietly disappeared.
❗ Important
Contracts, offer letters and legal drafts are the last documents you should upload to a free web service. Both files are read and diffed inside your browser — neither one leaves your machine.
🎭 Text diff vs visual diff: each one lies in a different way
This is the part every other comparison tool skips, and it's the reason you need more than one mode.
| Text diff | Visual (pixel) diff | |
|---|---|---|
| Compares | Extracted characters | Rendered page images |
| ✅ Catches | A changed number, a deleted clause, a swapped name | A moved logo, a changed font, altered spacing, a resized image |
| ❌ Misses | Anything about appearance — same words, wildly different layout looks identical | — |
| 🚨 False alarms | — | A reflowed paragraph. Add one word on page 2 and every following line shifts; a pixel diff lights up 40 pages that contain no real change. |
| Blind spot | Scanned PDFs. No text layer → nothing to compare → "no differences found" on two obviously different documents. | Trivial anti-aliasing noise between renderers. |
The rule of thumb:
- 📝 Text diff for a contract or a draft you're negotiating. You care about words.
- 👁️ Visual diff for artwork, a certificate, a form template, or any scanned document where text extraction gives you nothing.
- 📐 Layout diff when a document "looks wrong" but the words are identical.
⚠️ Warning
If a text comparison reports zero differences between two files you know differ, suspect a scanned PDF. No text layer means nothing to diff. Switch to visual mode.
🧭 How it works
✨ What's inside
| ### 🎨 Colour-coded changes Green added, red removed, amber modified — at word level, not just "this page differs". You read the change, not hunt for it. | ### 🔀 Four comparison modes Text, visual, layout and page-by-page. Because a diff that only works one way will confidently miss the change that matters. |
| ### 📑 Exportable report A downloadable summary of what changed — the thing you actually attach to an email saying "here's what they altered". | ### 🔒 Zero upload Both documents stay local. No Adobe subscription, no account, and no confidential draft sitting in someone's processing queue. |
🛠️ Real jobs
| Situation | What you're looking for |
|---|---|
| ⚖️ Contract came back "with minor edits" | The clause that was quietly deleted. |
| 📄 Offer letter v1 vs v2 | Whether the notice period or the bonus wording moved. |
| 🧾 Invoice reissued by a vendor | Which line item changed and by how much. |
| 🏗️ Drawing or spec revision | Dimensions and notes that differ between revisions. |
| 📚 Textbook or policy edition | What's new in this year's edition. |
| 🖼️ Print proof vs approved artwork | A moved logo or a substituted font — visual mode's home turf. |
📖 Four steps
1. Open → tooladda.online/compare-pdfs.html
2. Drop → version A and version B
3. Mode → text for wording, visual for scans/artwork
4. Read → highlighted diff, then export the report
▶ Compare now — tooladda.online/compare-pdfs.html
💡 Tip
Run text mode and visual mode on anything important. Text mode tells you what the document says; visual mode tells you what it looks like. Signing based on only one of those is how surprises happen.
❓ FAQ
Is it free? Do I need Adobe?
Free, no signup, and no Adobe Acrobat — comparison is a paid Acrobat Pro feature; this runs in your browser for nothing.
Are my documents uploaded?
No. Both files are parsed and diffed locally. That's the main reason to use this for contracts.
Why does it say "no differences" when the files clearly differ?
Almost certainly a scanned PDF with no text layer. Text mode has nothing to read. Use visual mode.
Why is the visual diff lighting up whole pages?
A reflow. One inserted word pushes every following line down, so the pixels genuinely differ everywhere even though the wording is unchanged. Read text mode for the real edits.
Can it compare documents with different page counts?
Yes — page-by-page mode aligns what it can and flags pages that exist in only one version.
Can I compare Word files?
Export both to PDF first, then compare. Same content, and you avoid Word's own revision-tracking noise.
🔬 Under the hood
- Client-side PDF parsing and rendering in vanilla JavaScript — no upload endpoint.
- Text mode diffs extracted text at word granularity; visual mode overlays locally rendered page bitmaps.
- Report generated in-browser.
- Works offline once loaded.
Originally published on ToolAdda, where Compare PDFs runs free in your browser — nothing is uploaded, nothing leaves your device.
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