Compress a PDF
Shrink a PDF's file size — entirely in your browser, no upload.
Drag & drop your file here
or click to choose — your file is processed locally and never uploaded
How to compress a PDF
- 1
Open your PDF
Drop in the file. It's read locally and never uploaded.
- 2
Pick a compression level
Choose how aggressively to shrink the file. Higher compression means a smaller result.
- 3
Download the smaller PDF
Compression runs on your device; download the optimized file when it's done.
Shrink files without uploading them
Compressing a PDF online means uploading the very file you're trying to keep small — and private. pdfnoupload compresses in your browser instead. The first time you use it, a compression engine (WebAssembly) downloads once; after that it's cached, so repeat compressions are fast and the engine even works offline. Your document itself is never uploaded.
Control quality vs. size
Pick a compression level to balance file size against visual quality — lighter for archiving, stronger for email attachments. Because the work runs in a Web Worker, the page stays responsive while it processes. The optimized PDF downloads directly to you, with no watermark and no server involvement.
Frequently asked questions
Is my PDF uploaded to compress it?+
No. The compression engine runs in your browser via WebAssembly. Verify zero uploads in DevTools → Network.
Why is there a one-time download the first time?+
The compression engine is a WebAssembly module that loads once, then is cached for instant, offline reuse.
How much smaller will my PDF get?+
It depends on the content. Image-heavy and unoptimized PDFs shrink the most; already-optimized files may change little.