PDF Compressor
Compress PDF by flattening pages and optimizing images.
PDF Compressor tool interface
How to compress a PDF file online
Upload your PDF
Click the Add PDF file button and select the PDF you want to compress from your device.
Choose compression level
Select the desired compression level or quality setting based on your size and clarity requirements.
Start compression
Click the Compress PDF button and let the tool process your file in the browser.
Download the compressed file
Once processing is complete, download the optimized PDF to your device.
Frequently asked questions
Does this PDF compressor upload my file to any server?
No. All compression happens inside your browser using pdf.js and pdf-lib. Your PDF never leaves your device, and nothing is uploaded or stored.
How does this tool compress a PDF?
Each page is rasterized into a JPEG at a chosen quality level (low, medium, or high compression). The JPEGs are then rebuilt into a new PDF.
Why does the text inside my PDF become non-selectable?
The compressor flattens text, vectors, and fonts into images to achieve maximum compression.
What do the compression levels mean?
Low = best quality, Medium = balanced, High = smallest size but lower clarity.
Why can I upload only one PDF at a time?
The tool is designed for single-file compression.
Why does the tool say the PDF engine is still loading?
pdf.js loads in the background. Slow networks may cause slight delays.
Why does compression sometimes fail?
Possible reasons: corrupted PDF, password lock, extremely large pages, or low device memory.
Does the compressor keep my original PDF name?
The output is downloaded as 'compressed.pdf' to avoid conflicts.
Why is the page count not detected?
If pdf.js cannot parse the PDF, metadata like page count cannot be retrieved.