PDF Compressor
Shrink PDFs with the same Ghostscript engine the big websites use — but running privately in your browser. Your file never leaves your device.
Drag & drop a PDF here
or click to browse your device
One PDF at a time · first run downloads a 15 MB engine (cached after)
Your files never leave your device.
Compressed PDF is ready
How to compress a PDF
- Add your PDF — drag it onto the box or click to browse. You'll see the file name and size before anything happens.
- Choose a compression level. Balanced (150 dpi) is right for most cases; Smallest (72 dpi) for strict email limits; High quality (300 dpi) if the document will be printed.
- Click Compress PDF. The first run downloads the compression engine once (about 15 MB, then cached). Download your smaller PDF when it finishes.
What PDF compression actually does
A PDF's bulk is almost always its embedded images — scanned pages, photos, screenshots. Text and vector graphics are tiny by comparison and stay untouched. The compressor (real Ghostscript, the same engine behind the popular web tools, compiled to run locally) rewrites the document: embedded images are downsampled to your chosen resolution and re-encoded efficiently, unused objects and metadata are stripped, and content streams are re-compressed. The result opens in every PDF viewer exactly like the original — same pages, same order, same text — just a fraction of the size.
Typical savings: 50–90% on scanned documents and photo-heavy files. A 25 MB scan commonly becomes 2–4 MB at the Balanced setting, well under the attachment limits that block submissions.
Choosing the right level
- Balanced (150 dpi) — the sweet spot. Photos look crisp on screens at normal zoom; fine for email, portals and archiving.
- Smallest (72 dpi) — for hard size caps. Images get slightly soft at high zoom; text stays perfectly sharp.
- High quality (300 dpi) — print-ready. Use it for documents someone will print at full size.
Honest limitations
If a PDF contains no images or its images are already heavily optimized, there's little to remove — the tool then keeps your original rather than returning something bigger. Password-protected PDFs can't be opened (remove the password first). And while 99% of documents come through perfectly, always glance at the result before deleting your original — that's good practice with any compression tool.
Frequently asked questions
Are my PDFs uploaded to a server?
No. The compressor runs a real Ghostscript engine compiled to WebAssembly, entirely in your browser. Your document never leaves your device — you can even disconnect from the internet once the page is loaded.
Which quality level should I choose?
Balanced (150 dpi) suits most documents viewed on screen. Smallest (72 dpi) is for email limits and quick uploads where slight softness in photos is acceptable. High quality (300 dpi) is for printing. Text and vector graphics stay sharp in all three.
Why does the first compression take a moment to start?
The compression engine (a 15 MB WebAssembly build of Ghostscript) downloads once and is then cached by your browser. Later compressions start instantly.
Why did my PDF barely shrink?
Most of a PDF's size is embedded images. If the document contains no images or its images are already well compressed, there is little to save. Text-only PDFs are already small. The tool never returns a bigger file — it keeps your original in that case.
Does it work on password-protected PDFs?
No — encrypted PDFs cannot be processed. Remove the password in your PDF reader first.
Is there a file size limit?
No artificial limit. Very large files (hundreds of MB) may take a minute and depend on your device's memory; typical documents compress in seconds.