About this tool
Many mailboxes and upload forms limit the file size, and scanned documents or PDFs from some programs are often needlessly large. Common causes are weakly compressed data streams and images stored losslessly instead of as JPEG.
This tool recompresses all data streams at the highest level, packs the objects into compressed object streams and removes unused resources – without any loss of quality. Optionally it stores large images as JPEG with adjustable quality. The processing is done by qpdf as WebAssembly in your browser; your file is not uploaded.
How it works
- Choose the PDF or drop it onto the area.
- Enable “Also compress images” if needed and set the image quality.
- Click “Compress”. The tool shows the size before and after.
- Download the smaller PDF; it is saved as …-compressed.pdf.
Frequently asked questions
How much smaller will the PDF get?
That depends a lot on how the PDF was created: already optimized files hardly shrink losslessly, PDFs from some programs considerably. For scans and photos not stored as JPEG, image compression usually helps most. If a PDF is already well compressed, the tool tells you and keeps the original.
Does the quality get worse?
Not without image compression: content, text and images stay exactly the same. With image compression, images are stored as JPEG, which can produce visible artefacts at low quality. 75 % is a good compromise.
Which images are compressed?
Images of at least 128 × 128 pixels that are not stored as JPEG already – and only if the JPEG is smaller. The resolution stays the same; existing JPEGs are not recompressed.
Does it work with protected PDFs?
Unlock PDFs with a password to open with Unlock PDF – Remove Password first. Then you can compress them and protect them again with Password-Protect PDF if needed.