Compress PDF files
Large PDFs are slow to email and often bounce off attachment limits, so DMI's compress tool re-encodes them into a smaller file using Ghostscript compiled to WebAssembly, running directly in your browser. The first compression downloads the engine (about 11 MB, cached by your browser afterwards); after that, everything happens on your device. Choose a quality preset, screen, ebook, or printer, and the tool shows the before-and-after file size so you can see exactly how much space you saved. If your browser cannot run the engine, the tool automatically falls back to compressing on our server over HTTPS, where the file is deleted immediately after processing.
How it works
- Add the PDF you want to shrink.
- Choose a quality preset: screen, ebook, or printer.
- Click Compress and download the smaller PDF.
Frequently asked questions
Is PDF compression free?
Yes, compressing PDFs with DMI is free, with no signup and no watermark. All three quality presets are included, and because compression runs in your browser there are no server limits to hit for normal use.
Are my files private and safe?
Compression normally runs entirely in your browser, so your file never leaves your device. Only if your browser cannot run the WebAssembly engine does the tool fall back to our server: the file is then uploaded over HTTPS, compressed, and deleted immediately. We log usage metadata, including IP address, filename, and sizes, for up to 12 months to prevent abuse; file content is never kept.
How much smaller will my PDF get?
It depends on the content and preset. PDFs full of high-resolution scans or images often shrink by 50 to 90 percent with the screen or ebook preset, while text-heavy documents compress less dramatically. The tool shows exact before-and-after sizes so you can compare presets.