Compress PDF Online Free: Reduce PDF File Size
Compress PDF files and reduce PDF file size in your browser. Your files are never uploaded, and no sign-up is needed.
Upload Your PDF
Files are processed locally in your browser and never uploaded
Runs entirely in your browser
Your PDF is read, compressed and saved inside this tab. The file itself is never sent to a server.
The site itself uses analytics and advertising cookies; where the law requires it (for example in the EU and UK), only with your consent. They never involve your files.
Files stay on your device
Processed in your browser and never uploadedNo upload wait
Speed depends on your file and your deviceQuality you control
Choose Low, Medium or High, or set a target size
- Files uploaded
- 0
- Languages
- 10
- Max file size (MB)
- 500
- Compression Levels
- 3
Frequently Asked Questions
Is my PDF file safe and secure?
What's the maximum file size I can compress?
Will compression affect PDF quality?
Can I compress password-protected PDFs?
Why is my compressed file sometimes not smaller?
How the PDF compressor works
Re-encode images
JPEG images inside the PDF are re-encoded at lower quality and, for Medium and High, resized. The file structure is re-saved with pdf-lib.
Runs in a Web Worker
Work happens in a background thread on your device, so there is no upload or download wait. Time depends on file size and device.
Files stay on your device
Your PDF is processed in your browser and never uploaded. Analytics and advertising cookies are separate from your files.
Why Choose Our PDF Compressor?
Free to Use: No registration and no payment; compress as many files as you like.
Privacy First: Files are processed in your browser and never uploaded.
High Quality: You choose the balance: Low keeps images close to the original, High gives the smallest file.
Cross-Platform: Works in current desktop and mobile browsers; nothing to install.
Complete PDF Compression Guide
Document types
Text-heavy PDFs (contracts, reports, books): usually shrink only a little, because text is already compact.
Image-rich PDFs (brochures, portfolios): the biggest savings, because embedded JPEG photos are re-encoded.
Mixed content (presentations, magazines): savings depend on how many JPEG images the file contains.
Scanned PDFs: often large, and they shrink well when the scan is stored as JPEG. Scans in other image formats are left unchanged.
Compression levels
Low: JPEG images re-encoded at 85% quality, not resized. The smallest change and the best quality.
Medium: JPEG quality 70%, and images are resized so the longest side is at most 1600 px. Document title and author are cleared.
High: JPEG quality 50%, longest side at most 1200 px. The smallest files, with visible quality loss on photos; title and author are cleared.
Best practices
Before compressing: remove pages you do not need with Extract Pages.
File size targets: many email providers limit attachments to about 20-25 MB. For an exact limit, use Compress PDF to Size.
Quality check: always review the compressed file before sharing it.
Backup: keep the original file; your browser never overwrites it.
Technical specifications and compatibility
Browser support
Chrome and Edge: current versions
Firefox: version 105 or newer
Safari: version 16.4 or newer
Browsers without OffscreenCanvas: only the file structure is optimized, images stay unchanged
Phones and tablets: iOS Safari 16.4+ and Chrome for Android; limited memory may stop very large files
What is supported
Standard PDF files (PDF 1.x)
PDF/A files open, but the result is not guaranteed to stay PDF/A
Password-protected or encrypted PDFs are not supported
Images with transparency masks, CMYK colors or non-JPEG encodings are left unchanged
Multi-page documents, up to 500MB per file
Technology
pdf-lib reads and rewrites the PDF structure
Web Workers keep the page responsive
All processing happens on your device; no file upload
Compression history (file names and sizes only) stays in your browser
pdf.js renders pages for target-size mode and image conversion
More PDF Tools
View All ToolsNeed to do more than compress? Explore the full PDF toolkit below.
Merge PDF
Combine multiple PDF files into one document. Drag and drop to reorder pages before merging.
Split PDF
Split a PDF into multiple files by page ranges. Each range becomes its own downloadable document.
PDF to Image
Convert PDF pages to PNG or JPEG images with adjustable quality and resolution.
Rotate PDF
Rotate PDF pages by 90, 180, or 270 degrees. Rotate individual pages or all pages at once.
Watermark PDF
Add custom text watermarks to your PDF with adjustable font, color, opacity, and position.
Extract Pages
Select and extract specific pages from a PDF into a new, smaller document.
Compress PDF to Size
Shrink a PDF to an exact target (100KB, 200KB, 500KB, or 1MB) for email limits, forms, and portals.
PDF to JPG
Convert PDF pages into smaller JPG images that are easy to share by email and social media.
JPG to PDF
Turn JPG photos and scans into one PDF. Reorder the pages, then pick a page size and margins.
PNG to PDF
Turn PNG screenshots and graphics into one PDF. Transparent backgrounds are kept.
Delete PDF Pages
Remove unwanted pages from a PDF. Click pages or type ranges such as 2, 4-6.