How much can I compress a PDF?

Compression results vary by content type. Image-heavy PDFs can be reduced by 70-90%. Text-only PDFs compress 20-40%. Our High Quality mode achieves 40% reduction with minimal quality loss. Medium mode provides 70% reduction (recommended for most uses). Maximum Compression achieves up to 90% reduction, ideal for web sharing and email attachments. The actual compression depends on your PDF content—PDFs with high-resolution images compress more than text-only documents.

Will compressing reduce PDF quality?

Quality impact depends on compression level. High Quality (40% reduction): Virtually no visible quality loss, safe for printing and professional documents. Medium (70% reduction): Slight quality reduction, not noticeable on screen viewing, good for most business uses. Maximum Compression (90% reduction): Noticeable quality reduction on close inspection, suitable for web previews and email. Our compression optimizes images intelligently—high-resolution photos are downsampled while text remains crisp and readable.

Is PDF compression free?

Yes, PDFlite.io offers completely free unlimited PDF compression with no file size limits, no page limits, no watermarks, and no hidden fees. You can compress as many PDFs as needed without creating an account. Paid plans ($21-$79/month) offer batch processing, API access, and priority processing, but basic compression is free forever for everyone.

How does PDF compression work?

PDF compression uses multiple techniques: Image downsampling (reduces high-resolution images to optimal screen/print resolution), JPEG compression (compresses photos with adjustable quality), duplicate object removal (eliminates redundant fonts and graphics), stream compression (uses FLATE algorithm to compress PDF structure), and font subsetting (includes only used characters from embedded fonts). PDFlite.io combines these methods intelligently based on your selected compression level to achieve maximum file size reduction while preserving usability.

Can I compress password-protected PDFs?

No, password-protected PDFs must be unlocked first before compression. Use PDFlite.io Unlock PDF tool to remove password protection (you must know the password), then compress the unlocked PDF. After compression, you can re-apply password protection using our Protect PDF tool if needed. This ensures security—we cannot access or compress encrypted content without authorization.

What file size is best for emailing PDFs?

Most email providers have attachment limits: Gmail/Outlook: 25MB limit, Yahoo: 25MB, Corporate email: Often 10-20MB limits. Best practices: Under 5MB for reliable delivery and fast downloads. Under 2MB for mobile-friendly emails. Under 1MB for newsletters and bulk emails. Use PDFlite.io Medium or Maximum Compression to achieve these targets. For files over 25MB even after compression, use cloud sharing links (Google Drive, Dropbox) instead of email attachments.

Does compression work on scanned PDFs?

Yes, scanned PDFs compress extremely well (often 80-90% reduction) because they contain high-resolution images of pages. Our compressor downsamples scanned images from 600 DPI to optimal 150-300 DPI for screen viewing, dramatically reducing file size while maintaining readability. However, if you need to edit scanned PDFs, run OCR (Optical Character Recognition) first using PDFlite.io OCR tool to make text searchable and editable before compression.

Can I batch compress multiple PDFs?

Yes, PDFlite.io supports batch compression. Upload multiple PDF files simultaneously (up to 20 files on free plan, unlimited on paid plans), select the same compression level for all files, and process them together. Each file is compressed individually with consistent settings. Download results as a ZIP archive or individually. Batch compression saves time when processing invoices, contracts, reports, or photo albums. Processing time: approximately 5-10 seconds per PDF.

Will compression affect PDF searchability?

No, compression does not affect PDF searchability or text content. Text-based PDFs remain fully searchable after compression because we preserve the text layer and only compress images and structure. For scanned PDFs, searchability depends on whether OCR was applied before compression. If your scanned PDF is already searchable (has text layer from OCR), compression preserves it. If not searchable, compression won't add searchability—run OCR first, then compress.

How secure is PDF compression?

PDFlite.io uses enterprise-grade security: Files are encrypted during upload (HTTPS/TLS 256-bit encryption), processed on secure servers (SOC 2 compliant infrastructure), and automatically deleted after 1 hour (configurable to immediate deletion on paid plans). We never store, view, or share your PDFs. All processing happens server-side with no human access. For maximum privacy, use our desktop app (available in paid plans) which processes files entirely on your computer without uploading to servers. Compressed PDFs are identical to originals except for reduced file size—no watermarks or tracking added.

Compress Up to 90% Smaller

Compress PDF Online Free

Reduce PDF file size by up to 90% while maintaining quality. Fast, secure, and completely free.

No registration required • No file size limits • No watermarks

90%

Max Compression

Average Process Time

2.8M+

Files Compressed

100MB

Max File Size

How to Compress PDF in 4 Steps

Simple, fast, and secure PDF compression

Upload PDF File

Drag-and-drop or click to upload your PDF. Supports files up to 100MB.

Choose Compression Level

Select High Quality (40%), Medium (70%), or Maximum (90%) compression.

Compress PDF

Click Compress. Processing takes 5-10 seconds with advanced algorithms.

Download Result

Download compressed PDF. No watermarks. Auto-deleted after 1 hour.

Why Choose PDFlite Compression

Professional-grade compression with unmatched features

Up to 90% Reduction

Advanced compression algorithms reduce file size dramatically while maintaining quality. Three compression levels: High Quality (40%), Medium (70%), Maximum (90%).

Lightning Fast

Compress PDFs in 5-10 seconds with optimized processing. Batch compress multiple files simultaneously for maximum efficiency.

100% Secure

256-bit encryption during upload. Files auto-deleted after 1 hour. SOC 2 compliant infrastructure. No human access to your documents.

No Watermarks

Completely free compression with zero watermarks, logos, or branding. Output PDFs are clean and professional.

Unlimited Use

Compress unlimited PDFs with no daily limits, no file size restrictions, and no account required. Free forever.

Works Anywhere

Browser-based compression works on Windows, Mac, Linux, Chromebook, tablets, and phones. No software installation needed.

Perfect For

Compress PDFs for any purpose

Business Documents

Reduce contract sizes for email attachments. Compress reports and presentations for faster sharing.

Contracts, Reports, Presentations

Team Collaboration

Share smaller files with colleagues. Upload to project management tools within size limits.

Shared Drives, Project Files

Cloud Storage

Save storage space on Google Drive, Dropbox, OneDrive. Compress archives before long-term storage.

Cloud Backup, Archives

Ready to Compress Your PDFs?

Join millions of users compressing PDFs with PDFlite. Free, fast, and secure.

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