Drop two PDFs and see every changed pixel highlighted in seconds — side-by-side, overlay, or changes-only view, with per-page change scores. Free, no account, the comparison runs entirely in your browser.
Original
Drop or click
Modified
Drop or click
The full upload-compare-review workflow takes most users under 60 seconds. The tool runs entirely in your browser — drop both PDFs, pick a view mode, navigate every change.
Click to browse or drag and drop two PDF files onto the upload areas — Original on the left, Modified on the right. Files are loaded into your browser's memory; they are not transferred to any server.
OneClickPDF offers three view modes for the same comparison data, so you can pick whichever suits the document and the question you are trying to answer. Side-by-side shows both PDFs with changes highlighted. Overlay blends both PDFs onto a single page. Changes-only hides everything identical and shows only what differs.
Each page in the comparison displays a change score — the percentage of pixels that differ from the same page in the other PDF. Use the jump-to-change buttons to skip directly to the pages with the most differences, ideal for fast-reviewing long documents.
The sensitivity threshold slider controls how much a pixel must change before the tool flags it as a difference. The default setting (30 out of 255) catches meaningful edits while ignoring minor rendering noise. Lower it to catch subtle font shifts; raise it to focus only on substantial edits.
Most online PDF comparison tools — Draftable, Adobe Acrobat’s compare feature, i2PDF, and textcompare.org — do text-based comparison. They extract the text from both PDFs and compare the words. This works well for plain documents where only the wording changed, but it has clear limitations:
OneClickPDF performs visual comparison at the pixel level. The tool renders both PDFs as images and compares every pixel on every page. Any visible change — text edit, font change, image replacement, layout shift, or even a one-pixel spacing difference — is flagged. This is the same approach used in design QA workflows and legal contract review where every visual difference matters, not just the words.
The trade-off: a pixel comparison cannot tell you what a paragraph used to say, only that it changed. If you need to read the deleted text itself, a text-diff tool will serve you better. If you need to confirm that nothing changed visually between two versions of a contract, a design proof, or a regulatory filing — only a visual diff will catch every difference.
The same comparison data, three lenses. Switch modes any time during review.
The original PDF on the left, the modified PDF on the right, both rendered at the same zoom level and synchronized as you scroll. Differences are highlighted in magenta on both sides. Use this view when you need to review changes line-by-line and want to read the surrounding context on each side.
Both PDFs are rendered onto the same page with their differences blended together. Where pixels match, you see the unchanged content. Where pixels differ, the change shows through. Use this view when you need to see exactly where content moved on the page — where a logo was repositioned, where a layout was tightened or loosened.
Everything that matches between the two PDFs is hidden in gray. Only the changed pixels are shown in magenta. Use this view when you are reviewing a long document and want to confirm at a glance that only the pages or sections you expected to change actually changed — and nothing else.
Every other PDF comparison tool in the top SERP — iLovePDF, Draftable’s online tool, PDF24, Adobe Acrobat Online, Sejda, Aspose, Xodo, PDFforge — uploads both PDFs to a remote server to run the comparison there. Some delete files after a short retention window. Some use HTTPS. None of them keep your file on your device, because their architecture cannot.
OneClickPDF is built differently. The full comparison runs inside your browser using your device’s processor. There is no upload, no server-side copy, and no retention policy to rely on — because there is nothing to retain.
Capability-by-capability: OneClickPDF is the only fully-free, browser-only tool that offers all three view modes plus per-page scoring and adjustable sensitivity.
| Feature | iLovePDF | Draftable | Sejda | Adobe | Ours |
|---|---|---|---|---|---|
| Free & unlimited | ✗ Daily | ✗ Paid | ✗ 3/hr | ✗ Paid | ✓ |
| No account needed | ✗ | ✗ | ✓ | ✗ | ✓ |
| Files stay in browser | ✗ | ✗ | ✗ | ✗ | ✓ |
| No ads or interruptions | ✗ | ✗ | ✗ | ✗ | ✓ |
| Side-by-side view | ✓ | ✓ | ✓ | ✓ | ✓ |
| Overlay diff mode | ✓ | ✗ | ✗ | ✗ | ✓ |
| Per-page change score | ✗ | ✗ | ✗ | ✗ | ✓ |
| Jump to change nav | ✗ | ✗ | ✗ | ✗ | ✓ |
| Changes-only view | ✗ | ✗ | ✗ | ✗ | ✓ |
| Sensitivity control | ✗ | ✗ | ✗ | ✗ | ✓ |
Competitor information was accurate at time of publication and may have changed.
Confirm that the only edits in v3 of a contract are the ones you negotiated, not silent changes elsewhere. Visual comparison catches modified numbers, changed dates, swapped clauses, and font-shift tells that text diffs miss.
Verify a designer applied your feedback exactly. Overlay view shows you in seconds whether a logo moved 4px or 40px, whether a margin was tightened, whether a colour swatch was replaced.
Ensure that a revised filing matches the previous version everywhere except the specific section flagged for amendment. Changes-only view answers this in one glance.
Confirm that a templated document set (1,000 invoices, 100 statements, every page of a manual) only differs in the variable fields you intended to change.
Compare two revisions of a paper, manuscript, or thesis to see precisely what an editor or co-author altered.
Spot every difference between two revisions of a technical specification, datasheet, or schematic — including font changes, dimension updates, and table edits text diffs would miss.
The compare tool runs in any modern browser — Chrome, Safari, Firefox, and Edge — on any device. Mac, Windows, and Linux desktops; iPhone and iPad on iOS Safari; Android on Chrome. All work without installing anything. Because the comparison runs locally, performance depends on your device’s processor, not on a server queue.
Drop both files, pick a view mode, navigate every change — under 60 seconds, no account, no upload.
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