What does PDF compression actually do?

It reduces image resolution/quality within the PDF, removes duplicate image data, applies more aggressive stream compression, strips unnecessary metadata, and removes embedded fonts if possible.

Will compressed PDFs print at lower quality?

At "Balanced" compression level, print quality is preserved for most documents. "Maximum compression" may reduce image sharpness. For archival/print PDFs, use "Minimum compression".

Can I compress a password-protected PDF?

No. Remove the password protection first, compress, then re-add password protection if needed.

What is the maximum PDF file size?

The tool handles PDFs up to 100MB. Very large PDFs (50MB+) may take longer to process depending on your device.

ToolsArena

Search tools...

PDF Compressor

Compress PDF files to reduce size while maintaining quality online.

Updated Mar 2026100% Private — runs in browser

Browser-based PDF optimization: This tool optimizes the PDF structure by removing unused objects and compressing internal streams. For image-heavy PDFs or maximum compression, use a desktop tool like Adobe Acrobat or Smallpdf.

Click to upload or drag and drop

PDF file only — max 100MB

How to Use PDF Compressor

1
Upload the PDF file you want to compress.
2
Choose compression level: Maximum Quality, Balanced, or Maximum Compression.
3
Click "Compress PDF" and wait for processing.
4
View the compression results: original vs compressed size.
5
Download the compressed PDF.

About PDF Compressor

Reduce PDF file sizes while keeping acceptable quality with our free PDF compressor. Smaller PDFs email faster, upload quicker, and fit within file size limits imposed by email clients and websites.

Key Features

3 Compression Levels: Maximum Quality, Balanced, or Maximum Compression — choose your trade-off.
Image Optimization: Compresses embedded images which account for most PDF size.
Size Preview: See the compressed file size before downloading.
No Watermarks: Clean output with no added marks or branding.

How Much Can a PDF Be Compressed?

PDFs with large embedded images can shrink 50–80%. Text-only PDFs may only reduce by 10–20%. Scanned documents (which are essentially image PDFs) can often be significantly reduced.

Privacy & Security

Uses pdf-lib entirely in your browser — your documents never leave your device. No signup required.