Reduce PDF File Size

Start with the Recommended preset — it removes structural waste and downsamples images to about 144 DPI, which typically cuts 50–80% with no visible change on screen. Escalate to Extreme only if you still need more, or switch to Target Size when a portal dictates an exact ceiling.

Choose by destination. Screen viewing and email: Recommended. Printing: Less Compression. A strict upload limit: Target Size. A huge scan where legibility is all that matters: Extreme. When unsure, run Recommended first and inspect the result — nothing is overwritten, so retrying costs you nothing.

Yes. This page is the software, and it runs inside the browser you already have. There is no installer, no extension and no account. The compression engine is WebAssembly executing on your own CPU, so it also works with the network disconnected.

Any modern browser with WebAssembly support: Chrome, Edge, Firefox, Safari, Brave, Opera and Arc, on desktop and mobile. Chromium-based desktop browsers are typically the fastest for very large documents.

Page dimensions, margins and layout are always preserved exactly. Print appearance only changes if images are downsampled below your printer's resolution. Less Compression holds images near 200 DPI, which prints cleanly on any office printer; avoid Extreme mode for anything going to paper.

Not while it is encrypted. A protected PDF has its content streams encrypted, so the compressor cannot read the images it needs to optimize. Remove the password in your PDF reader first, compress, then re-apply protection to the smaller output if you still need it.

Both, layered. Structural optimization — removing duplicate objects, dead revisions and metadata — is entirely lossless. Image downsampling and JPEG re-encoding are lossy, which is where the substantial savings come from. Text and vector graphics are never touched by either stage.

Compression is one-way, but your original file is never modified — it stays exactly where it was on your device. The compressed version is written as a separate download, so you always retain the source and can simply try again with a gentler preset.

Because it was already efficient. Files that are mostly text, or that were exported by a tool which already downsampled its images, hold very little recoverable waste. Large savings come from oversized embedded images — where there are none, there is little to reclaim.

No. Compression runs entirely inside your browser using WebAssembly. Your PDF is read into local memory, processed on your own CPU and written straight back to your downloads folder. No network request ever carries the file.