PDF Compress 🔒 Runs locally in your browser — nothing is uploaded.

About this tool

This tool makes a PDF smaller by re-serializing its internal structure more efficiently — it does not recompress or downscale the images inside the file, and it does not change how any page looks. Specifically, it re-saves the document using compressed object streams, a PDF feature that groups the file's many small internal objects (fonts, page dictionaries, cross-reference data, and so on) into fewer, compressed blocks instead of storing each one as plain, uncompressed text. That mainly helps files that were built with many separate small objects — for example a document assembled page-by-page by some tool or script — since those tend to carry more of this overhead.

Because of that, the size reduction you get is honest but variable: it depends entirely on how the source PDF was originally structured. A PDF already produced by a modern export pipeline that uses object streams (many are) may shrink by only a percent or two, or occasionally not at all. A PDF with a lot of small, uncompressed internal structure can shrink noticeably more. Either way, nothing in the visual content changes — every page, image, and piece of text comes through exactly as it was, just packaged more efficiently. If you need to actually shrink the images embedded in a PDF (recompressing photos at lower quality), that is a different, lossy operation this tool intentionally does not perform — everything here runs locally in your browser, and the file is never uploaded anywhere.

Frequently asked questions