What is the difference between the compression levels?

Low is lossless: it rewrites the PDF structure more efficiently without changing any content. Medium and High also re-encode photos and scanned images as JPEG at a lower quality and resolution, which can shrink image-heavy PDFs a lot at a small cost in image quality. Text and vector graphics are never rasterised.

Why didn't my PDF get smaller?

Some PDFs are already well optimised, or consist mostly of text, fonts or image types we do not re-encode (for example CMYK or JBIG2 images). In that case we say so, and you keep your original file.

Do you use Ghostscript?

No. Ghostscript is licensed under the AGPL, so pdfKOM uses qpdf (Apache-2.0) for lossless optimisation and the browser's own image codecs for image compression.

Compress PDF

Shrink a PDF by optimising its internal structure (lossless) and, optionally, re-compressing large images (lossy). You see the exact size before and after, and if the file can't be made smaller, we say so.

Drop a PDF file here

How to compress a PDF

Open the PDF you want to make smaller.
Pick a level. Low is lossless; Medium and High also shrink photos and scans.
Click Compress PDF and watch the progress.
Compare the before and after sizes, then download the smaller file.

Frequently asked questions

Merge PDFCombine several PDFs into one file, in the order you choose.
Split PDFExtract pages or split one PDF into several smaller files.
Image to PDFTurn JPG, PNG or WebP images into a single PDF.