PDF Compressor
Reduce PDF file size using stream compression and optional clean-up. Entirely in-browser — nothing is uploaded.
Compression level
Options
ℹ PDF compression primarily reduces structural overhead and uncompressed streams. Gains vary by file — text-heavy PDFs compress more than already-optimised ones.
What is PDF Compression?
PDF compression reduces the file size of a PDF by applying more efficient data encoding to its internal streams (images, fonts, page content). Smaller PDFs upload faster, consume less email attachment space, and are cheaper to store.
This tool compresses PDF streams in your browser using pdf-lib. Your file never leaves your device.
How to compress a PDF online
- Upload your PDF file.
- Click Compress to apply stream compression.
- The compressed PDF downloads automatically, with the file size reduction shown.
Frequently Asked Questions
How much smaller will my PDF get?
Results depend on the PDF's content. PDFs with lots of uncompressed text or metadata can shrink by 20-50%. PDFs with already-compressed images may see smaller reductions.
Does compression affect PDF quality?
This tool uses lossless stream compression (deflate). Text, vectors, and existing compressed images are preserved with no quality loss.
Can I reduce PDF size by reducing image quality?
This tool uses lossless compression only. For more aggressive reduction that re-compresses embedded images at lower quality, you would need a more advanced PDF editor.
Is there a file size limit?
No. All processing runs locally in your browser. The only limit is your device's available memory.