Compress Scanned PDF
Compress scanned document PDFs online for free. Our tool re-renders each page at your chosen DPI and JPEG quality — typically achieving 60–80% file size reduction while keeping text clearly readable. Supports DPI from 72 to 300. Fast, secure, and no signup required.
Compression Settings
Upload a scanned PDF to get started
Why Use Our Compress Scanned PDF Tool?
Optimised for Scanned Documents
Our compress scanned PDF tool re-renders each page at your chosen DPI and re-encodes it as JPEG — the most effective approach for scanned PDFs that contain embedded TIFF or high-resolution image data.
Secure Compress Scanned PDF Online
Your scanned PDFs never leave your device. 100% client-side processing in your browser ensures complete privacy — safe for confidential contracts, medical records, and legal documents.
Compress Scanned PDF — No Installation
Compress scanned PDFs directly in your browser. No software downloads, no plugins, no account required. Works on any device with a modern browser — Windows, Mac, iOS, or Android.
DPI & Quality Control
Choose from 72 to 300 DPI output resolution and 50% to 95% JPEG quality — giving you precise control over the file size vs. readability tradeoff for your specific use case.
Common Use Cases for Compress Scanned PDF
Scanned Contract Sharing
Compress scanned contract PDFs for email delivery and digital filing. Reduce multi-megabyte scans to a fraction of their size while keeping text clearly readable for signing and review.
Email Attachments
Compress scanned PDFs to meet email attachment size limits. Scanned documents from office copiers are often 5–20 MB — compress scanned PDF to under 1 MB for fast email delivery.
Government Portal Uploads
Government portals and official submission systems impose strict file size limits on scanned documents. Compress scanned PDF to meet these limits without losing document readability.
Digital Archiving
Compress large batches of scanned documents for long-term digital archiving. Use 150 DPI at 75% quality for a good balance between file size and readability for archival purposes.
Legal Document Management
Law firms and legal teams compress scanned case files, court documents, and evidence PDFs for digital case management systems that impose storage or upload size limits.
Mobile Scan App Output
Mobile scanning apps (CamScanner, Adobe Scan, Microsoft Lens) produce large PDF files. Compress scanned PDF output from these apps for sharing via WhatsApp, email, and cloud storage.
Understanding Compress Scanned PDF
What is a Scanned PDF?
A scanned PDF is a PDF file where each page is stored as a high-resolution image (typically TIFF or uncompressed JPEG) rather than as text and vector graphics. When you scan a physical document with a scanner, copier, or mobile scanning app, the output is a scanned PDF. These files are often very large — a single A4 page scanned at 300 DPI can be 1–5 MB. Our compress scanned PDF tool re-renders each page at a lower DPI and re-encodes it as JPEG, dramatically reducing file size while keeping text readable.
How Our Compress Scanned PDF Tool Works
- 1Upload Your Scanned PDF: Drag and drop or click to select any scanned PDF file. The compress scanned PDF tool accepts any PDF regardless of original file size or page count.
- 2Choose DPI and Quality: Select your output DPI (72–300) and JPEG quality (50–95%). 150 DPI at 75% quality is the recommended default — it produces readable text at a fraction of the original file size. All processing happens locally in your browser — your PDF never leaves your device.
- 3Download Your Compressed PDF: The compressed PDF downloads automatically. The result panel shows original size, compressed size, and percentage saved. Each page is re-rendered at your chosen DPI and stored as a JPEG image in the output PDF.
What Gets Changed During Scanned PDF Compression
- DPI Reduction: Each page is re-rendered at the selected DPI — the primary lever for file size reduction. Reducing from 300 DPI to 150 DPI typically reduces file size by 60–75%.
- JPEG Re-encoding: Pages are re-encoded as JPEG at the selected quality level, replacing the original TIFF or uncompressed image data with efficient JPEG compression.
- Metadata Removal: The output PDF strips embedded scanner metadata (device model, scan date, software) — reducing file size and protecting privacy.
- Text Searchability: The output PDF contains page images, not text layers. If the original scanned PDF had an OCR text layer, it will be removed in the output. Use an OCR tool after compression if searchability is needed.
Choosing the Right DPI and Quality Settings
Use 150 DPI at 75% quality for most scanned documents — this produces clearly readable text at 60–80% smaller file size. Use 96 DPI at 65% quality for maximum compression when only screen readability is needed. Use 200 DPI at 85% quality for documents that need to be printed or contain fine print. Use 300 DPI at 95% quality only when you need near-original quality with minimal compression.
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Frequently Asked Questions About Compress Scanned PDF
A compress scanned PDF tool reduces the file size of scanned document PDFs by re-rendering each page at a lower DPI and re-encoding it as JPEG. Scanned PDFs are typically very large because each page is stored as a high-resolution image. Our free compress scanned PDF tool works entirely in your browser — no upload to any server required.
Compression depends on the original scan resolution and your chosen settings. At 150 DPI and 75% quality, most scanned PDFs compress by 60–80%. At 96 DPI and 65% quality, compression can reach 85–90%. The result panel shows the exact original size, compressed size, and percentage saved.
Absolutely. Our compress scanned PDF tool processes all files entirely within your browser using pdfjs-dist and pdf-lib. Your PDF is never uploaded to any server, never stored remotely, and never transmitted over the network. This makes it completely safe for confidential contracts, medical records, and legal documents.
Yes, 100% free. No signup, no subscription, no premium tier, no file size limits on input PDFs, and no watermarks on the output. Our compress scanned PDF online tool is free forever.
150 DPI is the recommended default for most scanned documents — it produces clearly readable text at a fraction of the original file size. Use 96 DPI for maximum compression when only screen readability is needed. Use 200–300 DPI when the document needs to be printed or contains fine print that must remain sharp.
75% quality is the recommended default — it provides a good balance between file size and visual quality for most scanned documents. Use 65% for maximum compression when file size is the priority. Use 85–95% when the document contains photographs or detailed graphics that must remain sharp.
The output PDF contains page images, not text layers. If the original scanned PDF had an OCR text layer, it will be removed in the output. If text searchability is important, run OCR on the compressed PDF after downloading using a tool like Adobe Acrobat or an online OCR service.
A regular PDF contains text, fonts, and vector graphics — it is small and text-searchable. A scanned PDF contains page images (typically TIFF or JPEG) — it is large and not text-searchable unless OCR has been applied. Our compress scanned PDF tool is specifically designed for the image-heavy structure of scanned PDFs.
Since compression runs entirely in your browser, the practical limit depends on your device's available RAM. Most modern devices handle scanned PDFs up to 100 MB without issues. Very large multi-page scans may take longer to process — the progress indicator shows which page is being processed.