Reduce your PDF size for free
Drop a file and it is compressed inside your browser. Nothing is sent to a server, and there is no sign-up and no watermark.
Drop your PDF here
or click to choose a file · up to hundreds of MB
Choose PDF fileWhy this tool?
100% in-browser
Files never leave your device — compress sensitive documents with confidence.
Free & unlimited
No sign-up, no payment, no watermark. Compress as much as you like.
Powerful engine
Powered by Ghostscript — cuts image-heavy PDFs by up to 80%.
Frequently asked questions
Are my files uploaded to a server?+
No. All compression happens inside your browser and files are never transmitted anywhere.
How much smaller will my PDF get?+
Scanned or image-heavy PDFs typically shrink 50–80%. Text-only PDFs are already small and may change little.
Is there a file size limit?+
There is no server limit. Very large files may take longer depending on your device.
Is it really free?+
Yes. No sign-up, no payment, and no watermark.
Will the text get blurry?+
No. Text in a PDF is vector data and stays sharp after compression. Only the photos and scanned images inside the document are reduced in quality.
Does it work on a slow connection?+
Yes. After the engine loads once, no file data is transferred at all — speed depends only on your device, not your internet connection.
Can it compress password-protected PDFs?+
Encrypted PDFs cannot be opened by the engine and may fail. Remove the password in your PDF viewer first, save a copy, then compress it.
Does it work on mobile?+
Yes — recent Chrome, Safari and Samsung Internet all work. For very large files (hundreds of MB), a desktop with more memory is recommended.
PDF compression guide
Why are PDF files so large?
Most of a PDF's size comes from the images inside it. Scanners and office copiers typically scan at 300–600 dpi, which is why a contract of just a few pages can easily reach tens of megabytes. Embedded font files and leftover objects from editing add even more.
For reading on screen or uploading to a website, around 150 dpi is plenty sharp. Lowering an unnecessarily high resolution is the core idea of PDF compression — which is why scanned documents shrink dramatically with almost no visible quality loss.
How does this tool compress?
This tool runs Ghostscript — a PDF engine trusted by the print and publishing industry for over 30 years — compiled to WebAssembly so it executes right inside your browser. It resamples the images in your document to the resolution you choose, re-encodes them more efficiently, cleans up unused data and rewrites the file.
Typical online compressors upload your file to their server. This tool does the opposite: it brings the engine to your device instead. Because your file never leaves your machine, you can safely compress sensitive documents — contracts, ID scans, medical records — without any risk of exposure.
Which compression level should I choose?
'Recommended (150 dpi)' is the right default for most situations: sharp enough for reading on screen, with a large size reduction — ideal for email attachments and web uploads.
Choose 'Strong (72 dpi)' when size matters most, such as portals with tight upload limits. Fine print in scans may soften slightly. 'High quality (300 dpi)' is for printing or documents with detailed drawings you need to preserve.
If you have a hard limit — say a site that only accepts files under 10 MB — use the target-size mode. Enter 10 and the tool steps the resolution down automatically until it finds the best quality that fits.
Which PDFs shrink the most?
Scanned documents, photo-heavy reports and exported presentations typically shrink 50–80%. The higher the original image resolution, the bigger the savings.
Text-only PDFs exported straight from a word processor are usually only a few hundred KB to begin with, so there is little left to remove. Re-compressing an already-compressed file also gains little. If the size barely changes, your file was already optimized.