Advanced Features & Full Technical Specifications
This free PDF compressor is built using a modern browser-based processing engine that allows fast, secure, and high-quality PDF compression without requiring uploads or external servers. By leveraging PDF.js for rendering and the jsPDF engine for reconstruction, each page of your document is optimized using smart JPEG compression and metadata reduction techniques.
Key technologies include dynamic rasterization, adaptive image encoding, metadata cleanup, and proportional scaling. These allow the system to intelligently analyze each page and find the perfect balance between visual clarity and compact file size. Even large PDFs with dozens of pages benefit from significant reductions.
Core Features:
- Client-side PDF rendering with no file uploads required
- Adaptive JPEG compression with adjustable quality slider
- Automatic page scaling with preserved aspect ratio
- Multi-page batch processing engine
- Optimized PDF rebuild using jsPDF’s A4 page generator
- Metadata cleanup (XObjects, unused fonts, thumbnails)
- Real-time progress indicator per page
- Instant downloadable compressed output
- Mobile and desktop optimized interface
- No account, no registration, fully free forever
With these combined technologies, this compressor is ideal for reducing the size of scanned documents, image-heavy PDFs, reports, portfolios, academic files, and printable documents. It retains excellent readability while delivering dramatic size reduction.
Frequently Asked Questions
1. How does this PDF compressor reduce file size?
Each page is rendered into a canvas, then recompressed using JPEG encoding based on your selected quality level. The rebuilt PDF contains optimized images and cleaned metadata.
2. Are my files safe?
Yes. All processing happens in your browser. No file is uploaded, stored, or sent over the internet.
3. What is the ideal compression percentage?
40–60% is best for balance. 10–30% for small file sizes, 70–90% for high visual quality.
4. Will text become blurry?
At very low quality settings, text inside scanned images may blur. Normal PDFs remain readable.
5. Does it work offline?
If cached by your browser, yes — though the online libraries may require first load.
6. Does the tool support clickable links?
No. Because pages are re-rendered as images, embedded links are not preserved.
7. Can it compress password-protected PDFs?
Not currently. You must remove the password first.
8. Why does compression take time?
Each page is rendered individually. More pages = longer time.
9. What browsers are recommended?
Chrome, Edge, Firefox, Opera. Safari works but slower with large PDFs.
10. Why is output sometimes the same size?
If original PDF is text-only or already optimized, little compression is possible.
11. Does it preserve fonts?
Fonts become rasterized into images, so layout stays identical.
12. Can I compress multiple PDFs at once?
Not yet, but multi-file mode is planned.
13. Does it work on mobile?
Yes. Fully optimized for mobile browsers.
14. Can I choose specific pages?
Not now. The entire PDF is compressed automatically.
15. Why does my phone heat up?
Rendering pages uses CPU and GPU power. This is normal for heavy processing.
16. Is this tool 100% free?
Yes — unlimited usage, no login, no watermark.
17. What file types are supported?
PDF only. Image → PDF converter is planned.