Free PDF Compressor
Reduce the size of your PDF files with our powerful compression tool. Choose different compression levels to balance between file size and quality.
Upload PDF File
Drag and drop your PDF here, or click to browse
Max file size: 150MB
Compression Options
Higher compression may take longer but produces smaller files.
PDF Compression Tips
Choose the Right Level
Select the compression level based on your needs. Higher compression means smaller size but may reduce quality.
Best Practices
- Use Medium for general purpose documents
- Use Low when preserving image quality is important
- Use Maximum for the smallest possible file size
Benefits
- Easier to share via email
- Faster uploads and downloads
- Saves storage space
- Better for web publishing
How to Use PDF Compressor
Follow these simple steps to get the best results from our pdf compressor tool
Upload PDF File
Select your PDF document from your device. Supports files up to 150MB.
Choose Compression Level
Select the optimal balance between file size and document quality.
Download Compressed PDF
Get your optimized PDF with significant size reduction.
Why Choose Our PDF Compressor?
- Reduce PDF file sizes by 20-80% depending on content type
- Multiple compression levels for optimal results
- Maintains document structure and text readability
- Works with all types of PDF documents
- Free unlimited compression with no registration
- Complete privacy - no files uploaded to servers
Perfect For
- Email PDF attachments within size limits
- Reduce storage space for document archives
- Optimize PDFs for web download
- Compress presentations and reports
- Prepare documents for mobile viewing
- Reduce cloud storage usage
How to Compress a PDF File
- Upload your PDF file using the uploader above or drag and drop it into the designated area.
- Select your desired compression level based on your needs - High Quality for minimal compression or Maximum for smallest file size.
- Click the "Compress PDF" button to start the optimization process.
- Wait for the compression to complete - processing time varies based on file size and complexity.
- Preview the results and download your compressed PDF file instantly.
Why Compress PDF Files?
Professional Benefits
- Faster uploading and downloading - compressed PDFs transfer 5-10x quicker over the internet
- Reduced storage usage - save valuable space on devices, cloud storage, and servers
- Easy sharing via email - most email providers limit attachments to 25MB or less
- Better website performance - compressed PDFs load faster, improving user experience and SEO
- Lower bandwidth costs - reduced data transfer saves money for businesses and individuals
How Our PDF Compressor Works
Our advanced PDF compression tool uses intelligent algorithms to reduce file size while maintaining document quality:
- Image Optimization: Reduces resolution of embedded images where appropriate without visible quality loss
- Font Subsetting: Includes only the characters actually used in the document, reducing font data
- Object Stream Compression: Optimizes the internal PDF structure for maximum efficiency
- Metadata Removal: Strips unnecessary metadata and hidden information that adds bulk
- Duplicate Elimination: Removes redundant objects and data throughout the document
When to Use PDF Compression
- Job Applications: Meet upload requirements for resumes and portfolios (typically under 2-5MB)
- Academic Submissions: Submit papers and research documents within size limits
- Business Documents: Share reports, presentations, and contracts efficiently
- Legal Filings: Meet court and government portal requirements for document uploads
- Website Publishing: Improve page load times for downloadable resources
- Archiving: Reduce storage costs for long-term document retention
Privacy & Security
All processing happens directly in your browser using client-side JavaScript. Your PDF files are never uploaded to our servers, ensuring complete privacy and security. Your documents remain confidential and under your control throughout the entire compression process.
Best Practices for PDF Compression
- Start with the highest quality source file available for best compression results
- Choose "High Quality" compression for important documents like legal papers or portfolios
- Use "Maximum" compression for internal documents or when file size is critical
- Avoid compressing the same file multiple times as quality degrades with each compression cycle
- Always preview the compressed file before sharing to ensure quality meets your standards
- Keep original uncompressed files as backups for future use or re-compression
Common PDF Compression Questions
Will compression affect my PDF quality?
Our High Quality mode maintains excellent visual quality for most documents. Maximum compression may slightly reduce image clarity but text remains crisp and readable. Always preview your results before downloading.
What types of PDFs compress best?
PDFs with high-resolution images or scanned documents compress the most. Text-heavy documents with few images are already quite small and may not compress as dramatically.
Is there a file size limit?
Our tool can handle PDFs up to 100MB in size. For larger files, we recommend splitting them into smaller documents before compression.
How much smaller will my PDF become?
Compression results vary based on content. Image-heavy PDFs typically see 60-80% size reduction, while text-based documents may see 20-40% reduction. Files that are already optimized may compress less.
Frequently Asked Questions
Common questions about our PDF Compressor tool and file processing
PDF Compression Guide
Optimize your PDF files for any use case
Compression Levels
- Low Compression: Best quality, minimal size reduction
- Medium Compression: Balanced quality and size
- High Compression: Maximum size reduction
- Custom: Fine-tune for specific needs
Best Results For
- • Image-heavy PDFs (presentations, catalogs)
- • Scanned documents with photos
- • PDFs with embedded graphics
- • Large technical documentation
Everything you should know about PDF compression
A PDF is a container: text, vector drawings, embedded fonts and — usually the real problem — raster images all live inside one file. When a 40 MB report refuses to attach to an email, it is almost never the text that is heavy. It is a handful of photos or scanned pages saved at 300 DPI that nobody will ever print. PDF compression works by re-encoding those images, discarding duplicate resources and rewriting the object streams so the same document is described with fewer bytes.
CompressGo does that work inside your browser using the PDF-lib and Canvas APIs. Your document is read into memory, images are downsampled and re-encoded, unused objects are dropped, and the rebuilt PDF is handed straight back to you as a download. Nothing is transmitted, so confidential contracts, medical records, payslips and legal filings never leave the machine you are sitting at.
Because the work is local, speed depends on your device rather than on a queue. A 5 MB document is typically done in one to three seconds; a 100 MB scanned book takes longer and uses more memory, so close other heavy tabs before you start.
Real before / after results
Typical results measured on real documents. Your numbers will vary with page count and image density.
| File type | Original | After | What changed |
|---|---|---|---|
| Text-only contract (12 pages) | 1.4 MB | 0.9 MB | Stream compression and font subsetting only |
| Slide deck exported to PDF | 18 MB | 3.6 MB | Screenshots downsampled to screen resolution |
| Scanned document (30 pages) | 42 MB | 7.8 MB | Scans re-encoded at 150 DPI, still readable |
| Product catalogue with photos | 26 MB | 6.1 MB | Photo quality reduced to 70% JPEG |
| Vector-heavy CAD export | 9 MB | 8.2 MB | Little to gain — vectors are already compact |
CompressGo vs typical online compressors
| Feature | CompressGo | Typical upload-based tool |
|---|---|---|
| Files uploaded to a server | Never — processing runs in your browser | Yes, files are sent and stored temporarily |
| Works offline once loaded | Yes | No |
| File size limit | 150 MB | Often 10–25 MB on the free tier |
| Daily conversion cap | Unlimited | 2–3 files per hour |
| Watermark on output | No | Sometimes on free plans |
| Account required | No | Often for larger files |
Choosing a compression level
The three levels change how aggressively embedded images are resampled. Text, links, bookmarks and form fields are preserved at every level — only image fidelity is traded away.
- Low: safe for printing and archiving; expect 10–30% smaller.
- Medium: the right default for email and sharing; 40–60% smaller.
- High: for screen-only reading and web downloads; 60–80% smaller.
When compression will not help much
If a PDF is already optimised, or if it consists of vector line art, tables and text with no photographs, there is very little redundancy left to remove. Squeezing such a file harder mostly costs quality without saving bytes.
- Already-compressed PDFs exported by another optimiser.
- Pure vector drawings, invoices and generated reports.
- PDFs whose bulk is embedded fonts — split the file instead.
- Password-protected files: remove protection first, then compress.
Hitting a specific size limit
Portals frequently demand 100 KB, 200 KB, 1 MB or 5 MB. Start at Medium, check the result shown after compression, and step up to High if you are still over. For scanned pages, converting colour scans to a lower quality level usually gets you under a hard cap faster than reducing the page count.
If a form requires a strict limit and your document is mostly photographs, compress the images first with the image compressor and rebuild the PDF from them.
Quality you can verify
Every compressed file is downloaded, not previewed only, so you can open it in your usual reader and confirm that the text is still selectable and the figures still legible before you send it anywhere. If the result is too soft, re-run at a lower level — the original file on your disk is never modified.