Compress Large PDF Files

We enforce a 300 MB ceiling. In practice the real constraint is your device: a modern desktop with 8 GB of RAM handles 200 MB documents comfortably, while a phone may struggle past 50 MB. Because compression is memory-intensive, closing other browser tabs helps with very large files.

Compression time scales with page count and image resolution, and it runs on your own processor. A 300-page scanned document may take a few minutes. All work happens in a background Web Worker, so the page stays fully interactive and the progress bar keeps updating throughout.

Yes. Add them all and they are processed sequentially rather than in parallel — running several large jobs simultaneously would risk exhausting memory and crashing the tab. Each file gets its own progress bar and download button as it finishes.

Very well, because the file itself is never transmitted. Only the page and the compression engine are downloaded, once, and they are then cached. Uploading a 100 MB PDF to a server-based tool would consume 100 MB of your data allowance; here it consumes none.

Any modern browser with WebAssembly support: Chrome, Edge, Firefox, Safari, Brave, Opera and Vivaldi, on desktop and mobile alike. There is no minimum specification beyond that — older or lower-powered devices simply take longer on large documents.

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.

Yes, in two ways. Pick one of four calibrated presets for a quality-led decision, or switch to Target Size mode and enter an exact figure in KB or MB. Target mode steps through progressively stronger settings and stops at the highest quality that still fits your limit.

There is no page-count limit. The practical constraint is memory rather than pages: a 500-page text document compresses easily, while a 500-page high-resolution scan may exhaust memory on a lower-spec machine. Closing other tabs frees up headroom for very large jobs.

Yes. Bookmarks, the table of contents, internal cross-references, hyperlink annotations and interactive form fields all survive compression. Only the encoding of images and content streams is altered — the document's structural and navigational layers are preserved.

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.