Compress Scanned PDF Book – Shrink Image‑Based Books & Manuscripts

Have a large PDF book that was scanned – full of images and heavy? Our tool compresses scanned books, reducing file size while keeping text readable. Perfect for archiving old books, digitised manuscripts, and document collections. No sign‑up, no software – just upload and download.

Compress scanned PDF book – reduce image‑based book size with DonePDF
Compress Scanned Book – Free ✓ No installation • ✓ Secure • ✓ Instant download • ✓ Works on any device

Did you know? Scanned PDFs are often 10‑50 times larger than text‑based PDFs. A 300‑page scanned book can be 50‑100MB. With our compression, you can often reduce that to under 15MB, making it easy to share and store.

Why Compress Your Scanned PDF Book?

Scanned books create storage and sharing challenges. Here's why compression is essential:

Massive File Sizes

Each page is an image, leading to huge files that quickly fill up storage. Compression slashes the size.

Sharing Difficulty

Email, cloud, and messaging services often have size limits. A compressed scanned book fits easily.

Slow Upload/Download

Large files take forever to upload or download. Compression makes them fast to transfer.

Archiving & Backup

Archiving large scanned books consumes valuable space. Compressed files are easier to back up and store long‑term.

Scanned Book Size Comparison – What Can You Achieve?

Here's a typical breakdown of scanned book PDF sizes and the results you can expect with compression:

Scanned Book Type Pages Original Size After Compression (Max)
Text‑Heavy Scan (mostly text) 200‑300 30‑50 MB 6‑12 MB
Illustrated Scan (few images) 150‑250 40‑70 MB 10‑20 MB
Photo‑Heavy Scan (photos, art) 100‑150 60‑100 MB 15‑30 MB
Acceptable – some loss of fine detail 200‑400 100‑200 MB 20‑40 MB (may need Hyper Compress)

Results vary based on scan quality and content. Our tool finds the optimal balance for your specific scanned book.

How We Compress Scanned PDF Books

Scanned books are essentially image collections. Our compression targets the images effectively:

  1. Smart Image Downsampling: We reduce resolution to a screen‑friendly DPI (e.g., 150 DPI) and apply high‑quality resampling to maintain readability.
  2. JPEG Compression Optimisation: Images are recompressed with a quality level that balances size and clarity – you choose the intensity.
  3. Grayscale Conversion (optional): For text‑heavy scans, converting to grayscale can significantly reduce size without affecting readability.
  4. Metadata & Unused Data Removal: We strip EXIF and other extraneous metadata to save every possible byte.
  5. OCR‑Aware Optimisation: If text has been OCR’d, we preserve the text layer while compressing the background images, keeping the file searchable.

The result is a much smaller scanned book that's still readable on screens and perfect for archiving or sharing.

How to Compress Your Scanned PDF Book – Step by Step

Follow these steps to shrink your scanned book:

1

DonePDF Compress PDF and upload your scanned book PDF.

2

Choose your compression level – "High" for better quality, "Maximum" for smaller size.

3

Click "Compress" – processing takes a few moments.

4

Download your compressed scanned book PDF – ready for storage or sharing.

For extreme reduction, try our Hyper Compress tool. For better searchability, run OCR first, then compress.

Compression Levels – How They Affect Scanned Books

Scanned books respond differently to compression. Here's what each mode offers:

Mode Image Quality Size Reduction Best For
Standard Good – slight compression 30‑50% Archival, where quality is important
High Acceptable – some loss of fine detail 50‑70% Sharing via email, mobile viewing
Maximum Noticeable pixelation – but readable 70‑90% Extreme reduction, storage‑optimised archives

For scanned books, we recommend starting with "High" and adjusting based on your needs. Use "Maximum" only when size is the absolute priority.

Other Ways to Reduce Scanned Book PDF Size – Why Our Tool Is Best

Alternatives you might consider:

  • Re‑scanning with lower DPI: Time‑consuming and you lose the original quality permanently.
  • Desktop PDF software: Expensive and often complicated to get good compression for scanned images.
  • ZIP compression: Doesn't reduce PDF viewing size – recipients need to extract.
  • Manual image optimisation: You would need to extract, compress, and re‑insert each page – extremely time‑consuming.

Our tool is fast, free, and specifically optimised for scanned books – giving you the best size reduction with minimal effort.

Pro Tips for Compressing Scanned PDF Books

  • Run OCR first – converting to searchable text often results in smaller files after compression.
  • Choose the right DPI – for screen use, 150 DPI is enough; for printing, keep 300 DPI but accept larger files.
  • Convert to grayscale – if your book is black‑and‑white, grayscale compression saves a lot of space.
  • Remove blank pages – if your scan includes blank sheets, remove them before compression.
  • Use "High" compression for readability – avoid "Maximum" if you need to keep details like small fonts or illustrations.
  • Batch compress – if you have multiple scanned books, process them together to save time.

Pro Tip: For extremely large scanned books (over 200MB), use our Hyper Compress tool – it applies aggressive JPEG compression and can reduce file size by up to 95%.

Troubleshooting – Getting the Best Results for Scanned Books

  • Images too pixelated? Use "High" compression instead of "Maximum" to preserve more detail.
  • File still too large? Try Hyper Compress or convert to grayscale.
  • Text becomes unreadable? This is unlikely with our compression, but if it happens, use "Standard" compression.
  • Upload stuck? Ensure your file is under 50 MB (free tier) or consider splitting.
  • Scanned book has multiple image formats? Our tool handles mixed content (JPEG, PNG, TIFF) uniformly.

Who Needs to Compress Scanned PDF Books?

  • Librarians – digitise and archive old collections efficiently.
  • Researchers – share scanned academic papers and journals.
  • Students – reduce the size of scanned textbook PDFs.
  • Archivists – preserve historical documents with smaller files.
  • Publishers – prepare digital versions of out‑of‑print books.
  • Government agencies – manage scanned records and reports.
  • Family historians – share scanned family trees and documents.
  • Anyone with scanned PDF books – save space and improve sharing.

Key Benefits of Compressing Scanned PDF Books

✅ Massive Space Savings

Reduce file size by up to 80% – store more books in less space.

✅ Faster Sharing

Email, upload, or transfer your scanned books quickly.

✅ Readability Preserved

Text remains legible – only the file size shrinks.

✅ Secure & Free

No sign‑up, end‑to‑end encryption, auto‑deletion.

🚀 Need extreme compression for large scanned books? Try Hyper Compress

Hyper Compress applies aggressive JPEG compression and grayscale conversion, ideal for shrinking scanned books down to 10‑20% of their original size – perfect for archiving and mobile access.

Open Hyper Compress →

Frequently Asked Questions About Compressing Scanned PDF Books

Can I compress a scanned PDF book without losing readability?

Yes. Our tool uses smart image compression that reduces the file size while keeping text legible. You can choose the compression level – "High" keeps more detail, "Maximum" gives the smallest file size. For best results, run OCR first to convert to searchable text, then compress.

What is the best DPI for compressing scanned books?

For screen reading and archiving, 150 DPI is usually sufficient. For print quality, 300 DPI is recommended, but that results in larger files. Our tool automatically downsamples images to an optimal DPI based on your compression setting.

How much can I reduce the size of a scanned PDF book?

Scanned books are image‑based and often very large. With "Maximum" compression, you can reduce size by 60‑80%. A 50MB scanned book can shrink to 10‑15MB. For even more reduction, try Hyper Compress or convert to grayscale.

Is it safe to upload my scanned book manuscripts?

Absolutely. We use TLS encryption and auto‑delete all files within 2 hours. Your content is safe and confidential.

Should I use OCR before or after compression?

We recommend running OCR first. This converts images to text, making the PDF searchable and often resulting in smaller file sizes after compression, because text can be stored more efficiently than images.

Will bookmarks and metadata be preserved?

If your scanned PDF already has bookmarks, they will be preserved. However, if the PDF is purely image‑based without text, bookmarks are unlikely to exist. Metadata is stripped to save space, but you can add it back later if needed.

How long does it take to compress a scanned book PDF?

Compression time depends on file size and page count. A 200‑page scanned book usually takes 1‑3 minutes. Larger files may take a bit longer.

Compress Your Scanned PDF Book – Free

Upload your scanned book PDF and get a smaller version that's perfect for storage, sharing, and archiving – fast, secure, and easy.

Compress Scanned Book – Free

Compressing scanned PDF books

Scanned books are essentially a series of images, making them very large. Our tool downsamples images to 150 DPI and applies aggressive JPEG compression. For extreme reduction, convert to grayscale – this can reduce file size by 30‑40% without affecting readability.

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