How to Compress a PDF and Reduce Its Size

Compress a PDF in three steps

1. Open Compress PDF and drop your file onto the page. It is read by your browser, not uploaded.
2. Choose a level: Strong for the smallest file, Balanced for most documents, or Light to keep more detail.
3. Press Compress PDF. The result shows the original and new size, so you can check it fits your limit before downloading.

Why some PDFs shrink more than others

Most of a PDF's size usually comes from images. A scanned contract is really a stack of photos, so lowering their resolution and compressing them as JPG can cut the size dramatically.

A PDF exported from a word processor is mostly text and fonts, which are already compact. Redrawing those pages as images can make the file bigger, and the tool tells you when that happens so you can keep the original.

Which compression level to choose

• Strong (72 DPI): email attachments and upload forms with a strict limit, read on screen.
• Balanced (110 DPI): the right choice for most documents.
• Light (150 DPI): documents you will print or zoom into.

Things to know before you compress

Compressed pages are saved as images, so their text can't be selected, copied or searched afterwards. Keep the original if you need that.

If only part of a document is needed, Split PDF can remove the pages you don't need first, which often saves more space than compression. For photos you will add to a PDF later, Compress Image shrinks them before they go in.