Scanned PDFs are the largest type of PDF document you typically encounter.
Reduce PDF file size by up to 70% without losing quality, right in your browser. Need to edit the content first? Try our PDF to Word converter or PDF merger.
Upload your PDF file and compress it to reduce file size
PDF compression is the process of reducing the file size of a PDF (Portable Document Format) document without significantly compromising its visual quality or functionality. PDF compression works by optimizing images, removing unnecessary metadata, compressing text and graphics, and restructuring the PDF's internal structure. According to MDN Web Docs, PDFs can contain various types of content including text, images, vector graphics, fonts, and metadata, all of which can be optimized for smaller file sizes.
Compressing PDF files is essential for several reasons: reducing file size for email attachments (many email services have size limits), speeding up web uploads and downloads, saving storage space, improving document sharing efficiency, and ensuring compatibility with systems that have file size restrictions. PDF compression is particularly important for PDFs containing high-resolution images, scanned documents, or documents with embedded fonts and graphics.
Our PDF compressor uses advanced compression algorithms to optimize your PDF files entirely in your browser. This client-side processing ensures your PDF files remain completely private and secure. All compression happens locally, so your documents never leave your device or get uploaded to any server.
Large PDF files can be difficult to share via email, slow to upload, and consume significant storage space. High-resolution images and embedded fonts increase file size substantially.
document.pdf (8.5 MB)
Too large for email
Compressed PDFs are smaller, faster to share, easier to upload, and consume less storage. Images are optimized, metadata is removed, and the file structure is streamlined.
document.pdf (2.1 MB)
75% smaller, email-ready
Real data showing the benefits of compressing PDF files
According to MDN Web Docs, PDF files can contain uncompressed content that significantly increases file size. Client-side PDF compression enables users to optimize their documents for sharing and storage without compromising privacy or security.
Compressing PDF files offers numerous benefits for sharing, storage, and efficiency. Here are the key advantages of using our PDF compressor:
Many email services have file size limits (typically 10-25MB). Compressing PDFs allows you to send documents via email without exceeding these limits. Smaller files also upload and download faster, improving communication efficiency.
Compressed PDFs upload faster to cloud storage, content management systems, and web forms. This saves time and reduces bandwidth usage, especially important for users with slower internet connections or mobile data plans.
Compressed PDFs consume less storage space on your device, cloud storage, or servers. This is especially valuable when managing large document libraries, archives, or when storage space is limited or costly.
All PDF compression happens entirely in your browser using client-side JavaScript. Your PDF files never leave your device, aren't uploaded to any server, and aren't stored anywhere. This ensures complete privacy and security for sensitive documents.
Client-side processing means instant compression without waiting for file uploads or server processing. Compress PDF files in seconds, even for large documents. No internet connection required after the initial page load.
Choose from three compression levels (low, medium, high) to balance file size and quality. Low compression maintains high quality, while high compression maximizes file size reduction. Select the level that best fits your needs.
Companies like Adobe and iLovePDF offer PDF compression services, but they require file uploads to their servers. Our client-side approach ensures your documents remain completely private, making it ideal for sensitive business documents, legal files, medical records, and confidential materials.
Our PDF compressor uses advanced compression algorithms to optimize your PDF files directly in your browser. Here's how the compression process works:
Upload your PDF file. The tool analyzes the PDF structure, identifies images, fonts, and other content that can be optimized.
Based on your selected compression level, the tool optimizes images, removes unnecessary metadata, compresses text and graphics, and restructures the PDF for maximum efficiency.
Once compression is complete, preview the file size reduction and download your optimized PDF. The compressed file maintains visual quality while being significantly smaller.
To get the best results when compressing PDF files, follow these best practices:
PDF compression serves a wide variety of professional and personal needs. Understanding these use cases can help you determine when compression is the right solution:
Many email services limit attachment sizes to 10-25MB. Compressing PDFs allows you to send documents via email without exceeding these limits. This is essential for sharing reports, invoices, contracts, and other business documents.
Compressed PDFs also upload and download faster, improving communication efficiency and reducing bandwidth usage. This is particularly valuable for users with slower internet connections or mobile data plans.
Many web forms, job applications, and document submission systems have file size limits. Compressing PDFs ensures your documents meet these requirements and upload quickly. This is essential for online applications, document submissions, and content management systems.
Faster uploads also improve user experience, especially on mobile devices or slower connections. Compressed PDFs reduce waiting time and improve the likelihood of successful uploads.
Compressed PDFs consume less storage space on your device, cloud storage, or servers. This is valuable when managing large document libraries, archives, or when storage space is limited or costly. Organizations can save significant storage costs by compressing their PDF archives.
For individuals, compressed PDFs allow you to store more documents on your device or cloud storage without upgrading your storage plan. This is especially useful for mobile devices with limited storage capacity.
Mobile devices often have limited storage and data plans. Compressing PDFs before sharing via messaging apps, social media, or cloud services reduces data usage and storage consumption. This makes it easier to share documents on mobile platforms.
Compressed PDFs also load faster on mobile devices, improving the user experience when viewing documents on smartphones or tablets. This is essential for mobile-first workflows and remote work scenarios.
When archiving documents for long-term storage, compressing PDFs reduces storage requirements while maintaining readability. This is valuable for legal documents, medical records, financial statements, and historical archives where space efficiency matters.
Compressed archives are also faster to backup and restore, reducing backup time and storage costs. This is essential for organizations managing large document repositories.
PDFs containing many high-resolution images, scanned documents, or photographs can be very large. Compression optimizes these images while maintaining visual quality, making the documents more manageable and shareable.
This is particularly useful for portfolios, catalogs, presentations with many images, and scanned document collections. Compression can reduce file size by 50-70% while maintaining acceptable visual quality.
Upload your PDF file using the upload button or drag and drop it into the designated area. Select your desired compression level (low, medium, or high), then click Compress PDF. The tool will optimize your PDF by compressing images, removing unnecessary metadata, and optimizing the file structure. Once compression is complete, download your compressed PDF file.
Yes, our PDF compressor is 100% free to use. There's no registration required, no account needed, and no hidden fees. All PDF compression happens in your browser, so your files never leave your device and remain completely private.
Our PDF compressor offers three compression levels: Low compression maintains high quality with moderate file size reduction (10-30%), ideal for documents where quality is important. Medium compression provides a good balance between file size and quality (30-50% reduction), suitable for most use cases. High compression maximizes file size reduction (50-70% reduction) with some quality loss, perfect for web uploads and email attachments.
PDF compression can reduce quality depending on the compression level chosen. Low compression maintains near-original quality. Medium compression may slightly reduce image quality but remains suitable for most purposes. High compression may result in noticeable quality reduction, especially for images. Text and vector graphics are typically unaffected. Choose the compression level based on your quality requirements.
Absolutely. All PDF compression happens entirely in your browser using client-side JavaScript. Your PDF files never leave your device, aren't sent to any server, and aren't stored anywhere. This ensures complete privacy and security for sensitive documents, business files, and personal information.
Our PDF compressor can handle PDFs up to several megabytes in size. For optimal performance, we recommend files under 10MB. Very large PDFs with many high-resolution images may take longer to process, but all compression happens in your browser without any file size limits.
Currently, our tool supports standard PDF files. Password-protected or encrypted PDFs require the password to be entered first before compression. We're working on adding enhanced support for password-protected PDFs in a future update.
PDF compression specifically focuses on reducing file size through image compression and data optimization. PDF optimization is a broader term that includes compression but may also involve removing unnecessary elements, optimizing fonts, and restructuring the PDF for better performance. Our tool performs both compression and optimization to achieve the best results.
Guides for compressing PDFs in specific situations:
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Not all PDF compressors are equal. The main differences come down to where your file is processed, how much control you have over quality, and what the tool costs. Here is how the most common options compare.
| Feature | FixTools Compressor | Adobe Acrobat | macOS Preview | Print to PDF |
|---|---|---|---|---|
| Cost | Free | ~$15+/month | Free (macOS only) | Free |
| File processed on server | ❌ Browser-only | ✅ Cloud upload | ❌ Local | ❌ Local |
| Compression levels | 3 (low / med / high) | Fine-grained slider | Presets only | Fixed (low quality) |
| Preserves hyperlinks | ✅ | ✅ | Sometimes | ❌ |
| Preserves form fields | ✅ | ✅ | Sometimes | ❌ |
| Works on Windows | ✅ | ✅ | ❌ | ✅ |
| Requires install | ❌ None | ✅ Required | Built-in macOS | Built-in |
| Best for | Quick, private compression anywhere | Professional PDF workflows | Mac users, light compression | Last resort — strips metadata |
The “Print to PDF” workaround is worth calling out specifically: it is often suggested online as a quick compression trick, but it re-renders your PDF through the OS print system, which strips interactive elements, removes hyperlinks, flattens form fields, and can significantly degrade text sharpness. Use it only as a last resort when no other option is available.
From the FixTools Blog
How to Compress a PDF Without Losing Quality
Why PDFs get large, what compression actually does, and how to match quality settings to your use case.
Runs locally in your browser
No server upload during processing
No server-side file retention
No watermark added
Drop the PDF Compressor into a blog post, product docs, intranet, or school portal with one iframe. Processing, privacy, and usage limits are the same as on the full tool page.
Embed code
<iframe
src="https://www.fixtools.io/pdf/pdf-compressor?embed=1"
width="100%"
height="780"
frameborder="0"
style="border:0;border-radius:16px;max-width:900px;"
title="PDF Compressor by FixTools"
loading="lazy"
allow="clipboard-write"
></iframe>Attribution-friendly: a small "Powered by FixTools" link appears in the embed footer.
When a physical document is placed on a flatbed scanner or fed through a document feeder, the scanner's sensor captures reflected light as a pixel grid. The density of that grid is the dots per inch setting. Consumer and office scanners default to 300 DPI for documents, which produces 300 pixels per linear inch. An A4 page is approximately 11.7 inches tall and 8.3 inches wide, so a 300 DPI scan produces a raster image of 3,510 by 2,490 pixels, or about 8.7 megapixels per page. Even after JPEG encoding within the PDF container at quality 80, that single page weighs 500KB to 2MB. A 10-page scanned contract can easily reach 10 to 20MB. At 600 DPI, the default on some scanners for OCR accuracy, the same page is four times larger in pixel count and the file size scales proportionally.
The key insight is that 300 DPI is necessary for OCR accuracy and for producing clean printed output, but it far exceeds what any display device needs. A typical computer screen renders at 72 to 110 PPI. A Retina or 4K display at its native density reaches 220 to 260 PPI. An image displayed at 96 DPI on a 100 PPI screen is already rendering at near-native display density because every pixel in the image maps to approximately one pixel on screen. Storing the image at 300 DPI in a PDF that will only be read on screen wastes between ten and twenty times the image data. FixTools resamples embedded raster images from their original scanner DPI down to approximately 96 DPI, which is sufficient for all screen display purposes and for printing at standard office quality, because 600 DPI printers interpolate well from 96 DPI source images.
Greyscale and black-and-white scans compress more efficiently than colour scans because they contain less colour data per pixel. A greyscale scan at 300 DPI can reach 200 to 800KB per page. A black-and-white (monochrome) scan of a text page at 300 DPI may only be 50 to 200KB per page using CCITT Group 4 or JBIG2 encoding. Colour scans at 300 DPI are the largest because each pixel stores three colour channels of red, green, and blue. When compressing scanned PDFs, FixTools identifies each image stream's colour mode and applies the most efficient re-encoding: JPEG for colour and greyscale, more compact encoding for near-monochrome content. If your scanner produced a colour scan of a black-and-white document, switching the scanner to greyscale or monochrome for future scans will produce significantly smaller PDFs before any compression is needed.
It is worth understanding that compression on scanned content is fundamentally lossy in a way that does not affect digitally created PDFs. A native PDF stores text as vectors which can be re-rendered at any resolution without quality loss. A scanned PDF stores text as pixels, so when the image is downsampled, the visual representation of each character contains less detail. For body text at 10 to 12 point font scanned at 300 DPI, downsampling to 96 DPI leaves roughly four pixels per character stroke, which is enough for clear legibility on standard screens. For very small text, fine handwriting, or low-contrast print, the loss becomes visible. Inspecting the output at 150 percent zoom before sharing important documents is the simplest way to catch any problems early.
Upload your scanned PDF and select high compression. Scanned documents have no vector text to protect, so high compression produces excellent results: typically 70 to 80 percent smaller with text remaining clearly legible at normal screen zoom.
Step-by-step guide to compress scanned pdf files:
Open the PDF Compressor
Go to fixtools.io/pdf/pdf-compressor in your browser. No installation or sign-up needed and the page loads in under a second on a typical broadband connection.
Upload your scanned PDF
Drag the scanned PDF onto the upload area or use the file picker. Files at 300 DPI may be 10 to 50MB in size which is entirely expected for scanned content and well within the tool's capacity.
Select high compression
For scanned documents, high compression is appropriate because there is no vector text or fine line art to preserve at maximum quality. The raster images will be resampled to 96 DPI, which is sufficient for screen and office printing.
Compress and verify
Click Compress PDF. After downloading, zoom in on text in the output to confirm it remains legible. For typical printed text at 10pt or above, legibility is maintained, and any quality issues become obvious at 150 percent zoom.
Compare file sizes
Note the original and compressed sizes side by side. A 70 to 80 percent reduction is typical for colour scans, and a 20MB scanned PDF commonly compresses to between 4MB and 6MB depending on page count and visual density.
Common situations where this approach makes a real difference:
A legal firm scans 200-page client case bundles at 300 DPI for digital filing in the matter management system. Each bundle is 180 to 220MB. Court portals cap uploads at 30MB per submission, so the originals are unusable for direct upload. After high compression in FixTools, each bundle reaches 35 to 45MB. Splitting into two parts and compressing each produces 18 to 22MB files that upload cleanly within the portal limit, allowing the firm to file electronically rather than couriering physical bundles.
A GP surgery scans patient registration forms (three pages each) at 300 DPI colour. Each form is 9 to 12MB. The practice management system has a 2MB per-document limit, which blocked the entire planned migration to paperless records. High compression reduces each form to 1.4 to 1.8MB. All text including handwritten patient signatures and notes remains readable at 150 percent zoom on the practice's 1080p monitors, and the records project resumes without a software change.
A council archiving officer scans 50 years of planning permission documents at 300 DPI for a digital repository. Single-page decisions average 2.5MB each, producing a 500-document archive of 1.25GB. Medium compression reduces the average to 550KB per page, shrinking the archive to 275MB and fitting it on a standard USB drive for off-site backup. The smaller archive also indexes and searches significantly faster inside the repository's OCR-based search interface.
A self-employed builder scans receipts for expenses on a smartphone app that defaults to 300 DPI colour. Each receipt scan is 3 to 5MB. His accountant's portal has a 1MB per-attachment limit which had previously meant rejecting his uploads. High compression in FixTools reduces each receipt to 200 to 400KB while keeping amounts and supplier names legible. The monthly expense submission, which used to take a frustrating hour of trial and error, now completes inside twenty minutes.
Get better results with these expert suggestions:
Switch your scanner to greyscale for text documents
If you are scanning text-only documents such as letters, contracts, and forms with no colour graphics, switching your scanner setting from colour to greyscale reduces the raw scan size by 66 percent before any compression. A colour scan at 300 DPI might be 3MB per page; the same page scanned in greyscale is typically 800KB to 1.2MB. Applying FixTools compression to a greyscale scan produces an even smaller final file because the starting point already discarded the unnecessary colour channels.
Check if your scanner has a built-in PDF compression setting
Many modern office scanners including Canon imageFORMULA, Fujitsu ScanSnap, and HP Enterprise scanners offer built-in PDF compression settings in their scan profiles. Enabling a medium compression profile at the scanner level can produce PDFs of 200 to 500KB per page without any post-processing. If your scanner already compresses output well, FixTools compression may offer smaller additional gains, but it remains useful as a finishing step when the scanner output still exceeds a portal limit.
High compression is appropriate for scanned text documents
Unlike digitally created PDFs where high compression risks degrading photographs, scanned text documents benefit from aggressive compression with minimal visible impact. The human eye tolerates JPEG artefacts in text images more than fine photographic detail at typical reading distances. For scanned forms, contracts, and letters, high compression in FixTools is the correct default choice, and it leaves the photograph-friendly low setting for documents that genuinely contain photographic content needing the highest possible fidelity.
Run OCR before compressing for searchable archives
If you need your scanned PDF to be text-searchable for example for a document management system, run OCR on the original high-resolution scan first, then compress the OCR-processed file. Compressing before OCR can degrade character recognition accuracy for small or unclear text because the OCR engine has fewer pixels to analyse. Once the OCR text layer is embedded, compression of the image layer does not affect the searchable text in any way.
Other tools you might find useful:
PDF Merger
Merge multiple PDFs after compressing each.
PDF Splitter
Split large PDFs before compressing.
Image Compressor
Compress images before embedding in PDF.
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