Compress PDF
Shrink a PDF's file size by rebuilding it with an optimized internal structure.
About this tool
Rebuilds a PDF with a more efficient internal structure — deduplicated objects, compressed object streams, and stripped metadata — using the open-source pdf-lib library, entirely in your browser. This shrinks bloated or inefficiently-generated PDFs, but has little effect on files whose size is dominated by large embedded images (like scanned documents), since it doesn't re-encode image data.
Frequently asked questions
- Why didn't my file get much smaller?
- This tool optimizes the PDF's internal structure (object streams, duplicate data, metadata) rather than recompressing embedded images. If most of your file's size is scanned pages or high-resolution photos, structural compression alone won't shrink it much.
- Will this reduce PDF quality?
- No — no image or text content is altered or re-encoded, so visual quality and text remain identical. Only the file's internal packaging is optimized.
- Are my files uploaded anywhere?
- No — compression happens entirely on your device. Nothing is sent to any server.