Free PDF Compressor
Reduce PDF file size by up to 80% without quality loss. Compress large PDFs for email attachments, faster uploads, and reduced storage. 100% private — your files never leave your browser.
Compress PDF File
Drag & drop a PDF to reduce its size
Why Compress PDF Files?
Large PDF files create problems across business and personal workflows
Email Attachments
Most email services limit attachments to 10-25MB. Gmail: 25MB, Outlook: 20MB, Yahoo: 25MB. A single scanned document or report can easily exceed these limits. Compress PDFs to fit within email restrictions and avoid upload failures or delivery errors.
Cloud Storage Savings
Cloud storage costs money beyond free tiers. Google Drive: 15GB free, Dropbox: 2GB free, OneDrive: 5GB free. Compressing PDFs by 60-80% can triple or quadruple your effective storage capacity without paying for upgrades. Save money while storing more documents.
Faster Upload & Download
Large PDFs take minutes to upload/download, especially on slower connections. A 50MB PDF compressed to 10MB uploads 5× faster. Critical for form submissions with deadlines, sharing reports with clients, or uploading documents to government portals with timeouts.
Website Performance
PDFs embedded on websites or offered as downloads affect page load times and SEO. Large PDFs frustrate users on mobile or slow connections. Compressed PDFs improve user experience, reduce bandwidth costs, and help SEO metrics like Core Web Vitals.
Mobile Viewing
Mobile users often have limited data plans and slower connections. Large PDFs drain data allowances quickly and take forever to load. Compressed PDFs load instantly on 4G/5G, reducing frustration and improving accessibility for mobile users.
Online Form Submissions
Job applications, visa applications, university admissions, and government forms often have strict file size limits (usually 2-10MB per file). Scanned documents easily exceed these limits. Compress to meet requirements and avoid rejected applications.
How PDF Compression Works
Understanding visual compression and rasterization technology
PDF Analysis
Your browser reads the PDF using PDF.js library. Each page is analyzed for size, images, fonts, and complexity. The original structure is parsed and prepared for processing.
Page Rasterization
Each PDF page is rendered to a canvas at optimized resolution. High-quality PDFs render at 200-300 DPI, balanced quality at 150 DPI, extreme compression at 72-100 DPI.
Image Compression
Rendered pages are compressed as JPEG images with your chosen quality level. This removes embedded high-res images, complex vector graphics, and unnecessary metadata.
PDF Rebuild
Compressed images are assembled into a new PDF using jsPDF library. The result is a much smaller file with visual content preserved. Downloads automatically when complete.
Compression Level Guide
🔥 Extreme Compression
Size Reduction: 80-90% smaller
Quality: Low. Visible compression artifacts, text may be slightly blurry, images lose detail.
Best for:
- Documents you just need to read once
- Email attachments with strict size limits
- Archival documents where readability > quality
- Online form submissions with small file limits (2-5MB)
- Sharing via messaging apps with file size restrictions
Not recommended for: Professional presentations, important contracts, printing, official documents requiring clarity.
⚖️ Recommended Compression
Size Reduction: 60-75% smaller
Quality: Good balance. Text remains readable, images look decent, acceptable quality for most uses.
Best for:
- Standard email attachments
- Internal documents and reports
- Website downloads
- Student assignments and homework
- Everyday business documents
- Scanned receipts and invoices
Sweet spot: This is the default recommended setting for 95% of use cases. Provides excellent size reduction while maintaining acceptable quality.
💎 Less Compression
Size Reduction: 40-60% smaller
Quality: High quality. Text is crisp, images retain detail, minimal visible compression.
Best for:
- Professional presentations and proposals
- Client-facing documents
- Documents with important images/charts
- Legal documents and contracts
- High-quality scans you want to preserve
- Portfolio PDFs for job applications
Use when: Quality is more important than file size, but you still need some size reduction for practical sharing.
Technical Details & Limitations
⚠️ Important Limitations
- Text Searchability: Compressed PDFs convert pages to images. Text becomes non-searchable and non-selectable. Use OCR tools later if needed.
- Hyperlinks: Internal links, table of contents, and web links are removed during compression.
- Form Fields: Interactive PDF forms lose their input fields and become static images.
- Annotations: Comments, highlights, and annotations are flattened into the page image.
✅ What's Preserved
- Visual Content: All visible text, images, and graphics are preserved visually.
- Page Count: Same number of pages as original.
- Page Order: Pages maintain their original sequence.
- Page Size: Original page dimensions are preserved.
- Readability: Text remains readable (quality depends on compression level).
📊 Compression Method
- Technique: Visual compression (rasterization)
- Process: Convert pages to optimized images, rebuild as new PDF
- Image Format: JPEG compression on rasterized pages
- DPI Range: 72-300 DPI depending on quality setting
- Libraries: PDF.js for reading, jsPDF for creation
🔒 Privacy & Security
- ✅ 100% client-side processing in your browser
- ✅ Files never uploaded to servers
- ✅ No data stored or logged
- ✅ Works completely offline
- ✅ GDPR and HIPAA compliant (no data leaves device)
- ✅ Safe for confidential documents
💻 Browser Support
- ✅ Chrome 90+ (Recommended - fastest)
- ✅ Firefox 85+
- ✅ Safari 14+
- ✅ Edge 90+
- ✅ Opera 75+
- ⚠️ Mobile browsers (slower for large PDFs)
- ❌ IE11 not supported
📏 File Size Limits
- Recommended: Up to 50MB PDFs
- Maximum: Limited by device memory (typically 100-200MB)
- Page Count: No artificial limit (tested up to 500 pages)
- Processing Time: ~1-2 seconds per page on modern computers
- Memory: Requires ~2-3× PDF file size in RAM
PDF Compression Best Practices
📑 When to Use Visual Compression
Ideal scenarios:
- Scanned documents (already images, nothing to lose)
- PDFs with many high-resolution images
- Documents where searchability isn't critical
- One-time reading (receipts, tickets, temporary docs)
- Strict file size requirements must be met
Avoid for:
- Text-heavy documents needing searchability
- Forms that need to remain editable
- Documents requiring text copy-paste
- Contracts needing digital signatures
- Files already very small (< 1MB)
🎯 Choosing the Right Quality
Consider these factors:
Target File Size: If you need < 5MB for email, work backwards. A 30MB PDF needs extreme compression; a 15MB PDF only needs recommended.
Document Type: Text-only documents handle lower quality better. Image-heavy documents need higher quality to remain viewable.
Intended Use: Archival or professional use → less compression. Quick sharing or temporary use → extreme compression fine.
Original Quality: If original is already low-resolution (old scan), aggressive compression won't hurt much more.
Pro tip: Always try "Recommended" first. If still too large, try "Extreme." Never go lower quality than necessary.
💡 Optimization Tips
- Keep Original: Always save your original PDF. Compression is irreversible.
- Test First: Compress one copy, check quality before batch processing.
- Remove Unnecessary Pages: Delete blank or unnecessary pages before compressing.
- Combine with Other Tools: Use PDF splitter to separate documents, compress each part, then merge if needed.
- Rename Appropriately: Add "_compressed" to filename to distinguish from original.
- Consider Alternatives: For text-only PDFs, export to Word, save as new PDF with lower image quality.
Common Use Cases
🎓 Student Documents
Scenario: Submit assignments to school portals with 10MB limits. Scanned notes or textbook pages create huge PDFs.
Solution: Use recommended compression. Text remains readable, file size drops 70%. Easily fits within submission limits.
💼 Job Applications
Scenario: Attach resume + portfolio PDF. Application systems limit files to 5MB.
Solution: Use less compression for professional appearance while meeting size requirements. Quality matters for first impressions.
🏠 Real Estate Listings
Scenario: Property brochures with 20+ high-res photos create 50MB+ PDFs. Too large for email or website download.
Solution: Recommended compression reduces to 10-15MB. Photos remain attractive, downloads 5× faster for potential buyers.
✈️ Travel Documents
Scenario: Visa applications, flight itineraries, hotel bookings combined into large PDF.
Solution: Extreme compression for submission. Embassies care about content, not quality. Reduces 20MB to 3MB.
📊 Business Reports
Scenario: Quarterly reports with charts, graphs, data tables. Need to email to executives.
Solution: Less compression to keep charts readable and maintain professional appearance. 40-50% size reduction sufficient.
🏥 Medical Records
Scenario: Scanned medical reports, X-rays, test results for insurance claims or referrals.
Solution: Recommended compression. Critical that text remains readable. Complete privacy as processing is local.
Frequently Asked Questions
Is this PDF compressor really free?
Yes, completely free with no limits. Compress unlimited PDFs, no registration, no hidden costs, no premium tiers. All processing happens in your browser using free, open-source libraries (PDF.js, jsPDF), so there are no server costs to charge you for.
Are my PDFs safe and private?
Absolutely. Unlike most online PDF tools, your files never leave your device. All compression happens locally in your browser using JavaScript. Your PDFs are never uploaded, never stored, and never seen by us or anyone else. Safe for confidential documents, medical records, legal files, or any sensitive information. Works offline once the page loads.
Will compression reduce PDF quality?
Yes, intentionally. Visual compression trades quality for file size. The "Recommended" setting balances quality and size (60-75% reduction, good readability). "Extreme" prioritizes size (80-90% reduction, lower quality). "Less Compression" prioritizes quality (40-60% reduction). You control the trade-off. Text remains readable at all levels, though extremely compressed PDFs show visible artifacts.
Can I still search or copy text after compression?
No. Visual compression converts pages to images, removing the text layer. The compressed PDF is not searchable, and you cannot select/copy text. This is a trade-off for dramatic file size reduction. If you need searchability, consider alternative compression methods or use OCR software after compression.
How much smaller will my PDF be?
Typical results:
• Extreme: 80-90% smaller (30MB → 3-6MB)
• Recommended: 60-75% smaller (30MB → 7-12MB)
• Less: 40-60% smaller (30MB → 12-18MB)
Results vary based on original content. PDFs with many images compress more than text-only PDFs. Already-compressed PDFs may not reduce much further.
What's the maximum PDF size I can compress?
No artificial limit, but practical limits depend on your device's memory. Most modern computers (8GB+ RAM) handle PDFs up to 100-200MB fine. Very large PDFs (>100MB) take longer to process but will work. Processing time is roughly 1-2 seconds per page. A 500-page PDF takes 8-15 minutes.
Does compression remove pages or content?
No. All pages and visual content are preserved. The same number of pages, in the same order, with the same visible content. What's removed: text searchability, hyperlinks, form fields, embedded fonts, metadata, and high-resolution image data. Everything you see visually is kept, just compressed.
Can I compress password-protected PDFs?
No. Password-protected or encrypted PDFs cannot be processed without the password. If you know the password, unlock the PDF first using PDF password removal tools, then compress. If you don't know the password, you cannot compress the file.
Why does my PDF still seem large after compression?
Some PDFs are already optimized or compressed. If your original PDF is mostly text with few images, there's less to compress. Try extreme compression if you need smaller files. Alternatively, your PDF may have efficiency issues — try splitting it, compressing parts separately, then merging. If it's a scanned document at 72 DPI, it's already low-quality and won't compress much more.
What happens to PDF forms and fillable fields?
Interactive form fields are lost during compression. The visual content (field labels, text boxes) remains visible, but they become part of the page image and lose interactivity. If you've already filled out a form, the filled data is preserved visually. If you need an editable form, don't compress it. Fill it out first, then compress for archival.
Can I undo compression or restore the original?
No. Compression is permanent and irreversible. The original data (text layer, high-res images, vectors) is discarded. This is why file size reduces so dramatically. Always keep your original PDF file before compressing. Save the compressed version with a different name (e.g., "document_compressed.pdf").
How does this compare to other PDF compressors?
Most online PDF compressors upload your files to their servers, raising privacy concerns. Our tool processes everything locally in your browser — maximum privacy. Results are comparable to paid tools in terms of compression ratio. The main advantage is privacy, convenience, no upload time, and it's completely free with no file limits.