How does browser-based PDF compression work?

Each PDF page is rendered to a canvas element using PDF.js, then encoded as a JPEG image at the chosen quality level. A new PDF is built from those compressed images using pdf-lib. The result is a smaller file because JPEG compression discards visual detail that is often imperceptible at normal viewing sizes.

Will compressed text still be selectable?

No. The compression process converts each page to an image, so text in the resulting PDF is not selectable or searchable. This is a trade-off inherent to image-based compression. If you need selectable text, use Low compression which preserves the highest image quality.

Is my PDF uploaded to a server?

No. The entire compression process runs in your browser using PDF.js and pdf-lib. Your file is never uploaded to any server or transmitted anywhere.

Which compression level should I choose?

Low compression is best for documents you need to print or share at high quality. Medium is a good default for general use. High compression is ideal when file size matters most, such as email attachments or web uploads, and a slight quality reduction is acceptable.

Free Tool

PDF Compressor

Reduce PDF file size in your browser. Choose low, medium, or high compression — all processing runs client-side, no upload required.

Drop a PDF here or click to browse

or click to browse

How PDF compression works

This tool re-renders each PDF page as an image at a reduced scale and JPEG quality, then assembles a new PDF. The trade-off: smaller files at the cost of some image sharpness.

How to use

Drop a PDF or click to browse.
Choose a compression level.
Click Compress PDF.
Download the compressed file.

All processing runs in your browser — no files are uploaded to any server.

Frequently Asked Questions

How much will my PDF shrink?: Results vary by content. Image-heavy PDFs compress significantly. Text-only PDFs see minimal reduction since this tool compresses by re-rendering pages as images.

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