Compress PDF

This tool reduces a PDF's size by rendering each page and re-encoding it as a compressed image, then rebuilding those images into a new PDF. That approach is most effective on scanned documents and image-heavy files — the kinds of PDFs that are large precisely because they contain photos or high-resolution scans. For those, picking a lower compression level can cut the file size dramatically.

It is deliberately a rasterizing compressor, which makes the trade-off explicit: the text on each page becomes part of the image, so it is no longer selectable, searchable, or copyable in the output. If you need the text layer to stay live — for accessibility, search, or copy-paste — keep the original and share that instead, or use a lighter optimisation that preserves text.

Already-lean PDFs, especially text-only documents, may not shrink — and can occasionally grow, because turning crisp vector text into an image can add data. The tool shows the before-and-after size after every run, so you're never guessing: if it didn't help, simply keep your original file.

Three levels balance sharpness against size. High quality renders pages at a larger scale and a gentle JPEG setting, so the result stays crisp while trimming some weight — a safe choice when detail matters. Balanced is the recommended default and is what most scanned documents want. Maximum compression renders smaller and compresses harder for the smallest possible file, accepting softer images in return.

If a target portal or email has a hard size cap, start with Balanced and check the reported output size. If you're still over the limit, step up to Maximum compression; if the result looks too soft for what you need, step down to High quality. Because everything runs locally and instantly, it's quick to try a level, look at the size, and adjust.

Compression happens entirely in your browser: pdf.js renders each page and pdf-lib assembles the new file, all on your device. On this site, your PDF is not uploaded, which makes the tool appropriate for confidential documents you'd rather not send to an online service.

Encrypted or password-protected PDFs can't be processed — remove the protection first. Large or long PDFs use more memory and take longer, particularly on phones, because every page is rendered to a canvas before being re-encoded. If a very large file struggles, try splitting it first, compressing the parts, then merging the results.