Drag & drop your files here
Max 10 files • Max file size: 100MB
Accepted formats: .pdf
Reducing file size while preserving document content
PDF compression reduces file size by optimizing embedded images, subsetting fonts, and compressing internal data streams—without altering text content or document structure. Unlike raster image formats (JPG, PNG), PDFs are containers holding multiple elements: high-resolution images (often 300+ DPI from scanners), embedded fonts (Arial font = 450 KB uncompressed), page content streams (drawing commands), annotations, and metadata.
This tool uses Ghostscript—industry-standard PostScript/PDF processor created 1988, used by print shops and Linux distros for 35+ years. Compiled to WebAssembly for browser-based processing. Five compression techniques applied: (1) Image downsampling (300 DPI → 150 DPI = 75% fewer pixels, 40-70% file size reduction), (2) JPEG recompression (embedded images re-encoded at optimal quality, 20-50% additional reduction), (3) Font subsetting (embed only used characters, not entire font, 5-30% reduction), (4) Stream compression (Flate/ZIP on page content, 10-25% reduction), (5) Metadata removal (author, creation date, software info removed for privacy, 1-5% reduction).
Scanned documents compress most (70-90% reduction), text-only PDFs compress least (10-30%). Mixed content (text + images): 40-60% reduction. Already-optimized PDFs (Adobe Acrobat): 0-15%. Presentations exported to PDF: 50-70%. This variation is due to image content—images compress significantly, text is already compact.
Fast, free, entirely in your browser
Drag and drop PDF files onto the page, or click "Add PDFs" to browse. Up to 20 files at once (100MB maximum per file). Accepts password-protected PDFs (unlock before compression), scanned documents, forms, presentations, any PDF version.
Four quality presets: High Quality (300 DPI, JPEG Q92, 20-40% reduction, print-ready), Balanced (150 DPI, Q85, 60-70% reduction, recommended), Smaller File (96 DPI, Q70, 75-85%, email-friendly), Maximum (72 DPI, Q55, 85-90%, smallest files). Six use-case presets: Email, WhatsApp, Print, Web Upload, Archive, eBook. Target Size feature: specify exact size (100KB, 200KB, 1MB, 2MB), algorithm finds optimal settings automatically.
Processing takes 5-30 seconds per file depending on size and complexity. Download individually or as ZIP for batches. Powered by Ghostscript WASM (~10 MB library, loads once from CDN, then cached). Web Worker keeps UI responsive during compression. "Never return larger" guarantee—if compression produces bigger file (rare with already-optimized PDFs), keeps original.
How Ghostscript reduces file size
Biggest impact: Reduces resolution of embedded images from high DPI (300+) to lower DPI based on use case.
Example: 300 DPI image = 3600×4800 pixels (17.3MP). Downsample to 150 DPI = 1800×2400 pixels (4.3MP). Result: 75% fewer pixels.
Re-encodes embedded images with optimized JPEG quality. Quality levels: Q92 near-lossless, Q85 excellent, Q70 good, Q55 artifacts visible.
Trade-off: Lossy compression—lower quality settings introduce visible compression artifacts (blockiness, loss of fine details).
Embeds only characters actually used in document, not entire font. Text looks identical, all characters render perfectly.
Example: Full Arial font = 450 KB (2000+ glyphs). Subset for "Hello World" = 6 KB (10 glyphs). Result: 99% reduction in font data.
Applies lossless Flate (ZIP) compression to internal PDF data streams: page content (drawing commands), font programs, uncompressed image data.
Always applied: No quality loss, always beneficial. Same compression as ZIP files.
Removes document properties: author name, title, subject, keywords, creation date, modification date, creator software (e.g., "Microsoft Word 2019").
Privacy benefit: High—removes identifying information, software used, when document created.
Choose your quality vs file size trade-off
Settings: Ghostscript /prepress preset, 300 DPI (no downsampling), JPEG Q92-95 (near-lossless), embeds all fonts.
When to use: Sending to print shop, professional documents, archival purposes, when quality is critical. Not for email (files still large).
Settings: Ghostscript /ebook preset, 150 DPI downsampling, JPEG Q85 (excellent), font subsetting, full stream compression.
Sweet spot: Best balance for 90% of use cases. General purpose, email attachments, website downloads, digital distribution.
Settings: 96 DPI (screen resolution), JPEG Q70 (good, visible compression at zoom), maximum stream compression.
Quality: Text sharp (vector-based), images show minor artifacts. Good for business documents, not suitable for print.
Settings: Ghostscript /screen preset, 72 DPI (web standard), JPEG Q55 (visible artifacts), aggressive compression.
Warning: Significant image artifacts, blockiness on gradients. Text readable but images degraded. Not suitable for professional use.
Target specific size for email, web forms, messaging
Target size compression automatically finds optimal quality settings to meet exact file size requirements. Specify your target (50KB, 100KB, 200KB, 300KB, 500KB, 1MB, 2MB, or custom), and the algorithm adjusts compression parameters (DPI, JPEG quality, stream compression) through four progressively aggressive strategies. Guarantees output file meets size requirement or returns closest possible.
Gmail: 25 MB limit (but target 1-5 MB for reliable delivery). Outlook: 20 MB limit. Corporate email: often 10 MB. Strategy: Target 1-2 MB for universal compatibility.
Government forms: 2-5 MB. Job applications: typically 2 MB. Insurance claims: 5-10 MB. Strategy: Check form specifications, target 10-20% below stated limit for safety.
WhatsApp: 100 MB document limit (target 2-5 MB for faster sending over cellular). Telegram: 2 GB limit (no compression needed). iMessage: 100 MB limit.
Strict web forms, preview thumbnails. Quality expectation: Visible compression, acceptable for text-heavy documents, not suitable for photos.
Understanding lossless vs lossy compression
Techniques:
Reduction: 10-30% typically. Quality: Zero loss—mathematically identical pixels, text perfect, vector graphics preserved.
Techniques:
Reduction: 40-90% depending on aggressiveness. Quality loss: Q85 (Balanced) shows minor artifacts at 200% zoom, Q55 (Maximum) shows significant blockiness.
Text preservation: Text ALWAYS remains sharp (vector-based, not affected by image compression).
You CANNOT achieve 90% reduction without quality loss. Physics of compression requires trade-offs. Lossless compression limited to 10-30% for typical PDFs. Extreme compression (80-90%) requires aggressive image downsampling and JPEG recompression—quality loss inevitable. Recommendation: Balanced preset (60-70% reduction, excellent quality) is sweet spot for 90% of use cases. High Quality preset if quality is non-negotiable (print, archival).
100% browser-based via Ghostscript WebAssembly
100% browser-based PDF compression via Ghostscript WebAssembly (industry-standard PDF engine compiled to browser). PDF files never leave your device—no upload to servers, no storage, no exposure. Unlike ilovepdf or smallpdf (require server uploads), we process everything locally in your browser's Web Worker. Ghostscript WASM (~10 MB library) loads from CDN once, then cached locally. All compression happens in isolated worker thread—no network communication during processing.
NDAs, agreements stay private
Tax returns, bank statements never exposed
Insurance claims HIPAA-compliant
Court filings, depositions secured
Bids, presentations protected
Resumes, applications never stored
No POST endpoint in codebase. Files stay in browser memory only. Web Worker processes PDFs in isolated thread—no network communication during compression. GDPR compliant by design—no data collection possible. Works offline after Ghostscript library loads. Reddit users (#10 ranking) explicitly seek "privacy-focused tool, no server uploads, no sign-up"—this tool delivers exactly that.
Everything you need to know about PDF compression
Add your PDF file (drag-drop or click "Add PDFs"), choose Balanced preset for 60-70% reduction with excellent quality, then click Compress. Processing takes 5-30 seconds depending on file size. Download individually or as ZIP. Works entirely in your browser using Ghostscript WASM—files never uploaded to servers.
Compress embedded images (reduce DPI from 300 to 150), recompress with JPEG, subset fonts (embed only used characters), apply Flate/ZIP compression to streams, remove metadata. Ghostscript handles all of these automatically. Use our Balanced preset for best results—60-70% reduction while maintaining excellent quality for screens and email.
Depends on compression type. Lossless compression (font subsetting, stream compression) = no quality loss. Lossy compression (image downsampling, JPEG recompression) = some quality loss on images. Text ALWAYS remains sharp (vector-based). High Quality preset (minimal loss), Balanced (excellent for screens), Smaller File (good quality), Maximum (visible artifacts).
Use High Quality preset (300 DPI, JPEG Q92, minimal compression). Achieves 20-40% reduction with near-zero quality loss—print-ready. For maximum lossless reduction, combine font subsetting + stream compression + metadata removal (10-30% reduction, mathematically identical output). Cannot achieve 60%+ reduction without some image quality loss.
Depends on PDF content type. Scanned documents: 70-90% reduction (high-res images, uncompressed). Photos in PDF: 60-80%. Mixed content (text + images): 40-60%. Text-only PDFs: 10-30% (text already compact). Already-optimized PDFs (Adobe Acrobat): 0-15%. Presentations exported to PDF: 50-70%. Image-heavy PDFs compress most.
Yes. This tool is 100% free forever—no registration, no file limits, no daily compression limits, no "upgrade to premium" prompts. Unlike freemium competitors (ilovepdf, smallpdf) that restrict features, we offer unlimited compressions with all quality presets and target size feature. Also free: Mac Preview (built-in compression).
Five common causes: (1) High-resolution images (300+ DPI from scanners), (2) Uncompressed embedded images, (3) Full fonts embedded (450 KB per font instead of 6 KB subset), (4) Unoptimized PDF structure (no stream compression), (5) Many pages with images. Scanned PDFs are typically massive (50-200 MB) because they're essentially collections of uncompressed photos.
Browser-based tools (like this one) are safest—files never leave your device, processed locally via WebAssembly. Avoid server-upload tools for confidential documents (contracts, financial, medical, legal). Our tool uses Ghostscript in Web Worker—no network communication during compression. GDPR compliant by architecture. For sensitive PDFs, browser-based is the only secure option.
Built-in: Open PDF in Preview, File → Export → check "Reduce File Size" (basic compression, limited control). Better: Use this tool in Safari for quality presets and target size control. Mac Preview uses Quartz filters (good but limited), our tool uses Ghostscript (industry-standard, more compression options).
Use Safari on iPhone/iPad to access this tool. Browser-based processing works on iOS (Ghostscript WASM supported). Upload PDF from Files app, iCloud Drive, or email attachment. Choose preset, compress, download. Processing may be slower on mobile (2-3x slower than desktop) but fully functional.
Yes. Scanned PDFs compress best—typically 70-90% reduction possible. Scanners create high-resolution images (300+ DPI, uncompressed). Ghostscript downsamples to 150 DPI (Balanced) or 96 DPI (Smaller File) and applies JPEG compression. Text remains readable. Perfect for compressing scanned contracts, receipts, invoices, or multi-page documents.
Most email limits: 25 MB (Gmail, Yahoo), 20 MB (Outlook), 10 MB (corporate email). Target 1-5 MB for reliable delivery across all systems. Use our Target Size feature: enter 1 MB or 2 MB, algorithm finds optimal settings automatically. Smaller files also send faster over cellular and Wi-Fi.
Reduce size 40-90% with quality presets (High Quality, Balanced, Smaller File, Maximum) or target specific size (100KB, 200KB, 1MB). Powered by Ghostscript—industry-standard PDF engine. Files stay private in your browser, never uploaded.
