Compress PDF files online for free
This free Compress PDF tool reduces the size of a PDF directly in your browser so it is easier to email, upload, or store. Add your file, choose a compression level with the slider, and the tool re-renders each page at a lower resolution and re-encodes the images to bring the size down. You instantly see the original size, the new size, and how much you saved before downloading.
Everything happens locally with JavaScript — your document is never uploaded to a server, so it stays private. The tool works on desktop and mobile and keeps working offline once the page has loaded. For files that are mostly photos or scans, the size reduction is largest; files that are already highly optimized may shrink less.
How to compress a PDF
Drop in your PDF, move the slider toward Max compression for the smallest file or toward Light to keep more detail, press Compress, review the before and after sizes, and download. If the result is not small enough, slide further and compress again.
Frequently asked questions
Is my PDF uploaded to compress it?
No. Compression runs entirely in your browser with JavaScript. Your file is never uploaded, stored, or shared with anyone.
Why did my text become non-selectable after compressing?
To guarantee a smaller size on any device without server software, pages are rendered to images and re-encoded. This flattens the page, so text is no longer selectable. Keep your original if you need editable text.
How much smaller will my file get?
It depends on the content. Scanned documents and photo-heavy PDFs shrink the most. Already-optimized or text-only PDFs may shrink less. The slider lets you trade quality for size.
Which compression level should I choose?
Recommended is a good balance for most documents. Use Max compression when you must hit a strict size limit, and Light when you want to preserve as much sharpness as possible.
Does it work on my phone?
Yes. It is fully responsive. Very large PDFs may take longer on older phones because rendering uses the device's memory.