How to Compress a PDF for Free (Without Uploading It)

Most of a PDF's size comes from images — scanned pages, photos, and high-resolution graphics. Documents that are purely text are usually small already. That's why a 2-page scanned contract can be larger than a 50-page text report.

Compression works by optimising the file's structure and how its data is stored, reducing size while keeping the document readable.

Open the Compress PDF tool and drop in your file. Click Compress, and your browser optimises the document locally, then shows you the new, smaller size to download.

Because everything happens on your device, even confidential files stay private — there's no server copy. It's free, with no account and no watermark added to your document.

It depends entirely on the file. Image-heavy PDFs often shrink dramatically, while documents that are already optimised may only reduce a little. If a PDF barely changes, it's usually because it was already well-compressed.

If you need an even smaller file, consider whether every page is necessary — removing or extracting only the pages you need can cut size further.