Toolkist

PDF Compressor

Reduce PDF file size by re-encoding images — all in your browser.

Drop a PDF here

PDF files only

About PDF Compressor

Reduce PDF file size by re-encoding embedded JPEG and PNG images at lower quality, optionally scaling them down and stripping metadata. Uses pdf-lib running entirely in the browser — your file is never uploaded to a server. Works best on image-heavy PDFs; text-only PDFs will see little change.

Is my PDF uploaded anywhere?

No. Compression happens entirely in your browser using pdf-lib. Your file never leaves your device.

How does compression work?

The tool re-encodes embedded JPEG and PNG images at lower quality and smaller dimensions, strips metadata (for Screen/eBook/Printer levels), and reserialises the PDF using object streams.

Why is the output sometimes similar in size?

Text-only PDFs have very little image data to compress. Savings are largest on PDFs with many embedded photographs.

Is encryption supported?

Encrypted PDFs are loaded with ignoreEncryption — content is processed but the output is unencrypted.

Related: Image Compressor · File Diff

Keywords: PDF compressor, compress PDF browser, reduce PDF size, PDF optimiser, no upload PDF tool