Compress a scanned PDF
Scanners save every page as a high-resolution photo. We bring them down to a sensible resolution so your scan is 5–20× smaller and still crisp.
- 🔒 No upload
- ∞ No limits
- 🎯 Exact size
- ✓ No sign-up
Drop PDFs here or choose filesTap to choose PDFs
🔒 Compressed on your device — never uploaded · No limits · No sign-up
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Key facts
- Scanned pages are images; a 300 DPI colour A4 page can be 1–5 MB.
- Re-encoding at ~150 DPI usually cuts size by 80–95% with no visible loss on screen.
- Grayscale halves the size again for black-and-white documents.
- Processing happens on your device — scans of IDs and contracts are never uploaded.
How to compress a scanned PDF
- Drop your scanned PDF.
- Choose “Recommended”, or “Strong” for very large scans; tick Grayscale for text-only scans.
- Download the smaller PDF.
Why scans are so big
A scanner doesn't know what text is — it photographs each page. At 300 DPI an A4 page is about 2480 × 3508 pixels, and phone “scanner” apps often go higher. That's ideal for archives but far beyond what's needed to read on a screen or print on an office printer.
Best settings for scans
- Text documents: Strong + Grayscale — usually 30–80 KB per page.
- Documents with colour stamps or photos: Recommended — usually 100–250 KB per page.
- Archive quality: Light — still 40–70% smaller than most raw scans.
Frequently asked questions
Can I make a scanned PDF searchable?
This tool reduces size; it doesn't add OCR. Searchable scans that already have an OCR text layer keep it.
Will compression reduce quality?
Images are re-encoded at the level you choose. “Recommended” is visually indistinguishable for most documents on screen and in print. Text and vector graphics are never degraded.
Are my PDFs uploaded to a server?
No. Compression runs entirely inside your browser using JavaScript and WebAssembly-grade libraries. Your file never leaves your device, so confidential documents stay private. You can even disconnect from the internet after the page loads and it keeps working.
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