Make any PDF smaller without sending it to a server. Upload your document, adjust the quality slider to find the right balance between file size and clarity, and download the compressed PDF — all inside your browser.
Open PDF Compressor → free, no sign-inPDF files accumulate size from several sources: embedded fonts, high-resolution images, metadata, and redundant data structures. Most online PDF compressors deal with this by uploading your file to a server, processing it remotely, and sending the result back — which is fast but means your document passes through someone else's infrastructure.
This tool takes a different approach: it uses PDF.js to render each page of your PDF directly in your browser, re-encodes them as compressed JPEG images at your chosen quality level, and assembles a new, smaller PDF from those images using pdf-lib. The entire process happens locally — nothing is uploaded anywhere.
The quality slider is the key control. Higher settings preserve sharp text and fine detail; lower settings produce a much smaller file at the cost of some visual clarity. A setting of 80% is a good starting point for most documents — sharp enough for reading, small enough to email.
Start at 80% quality. If the result is still too large, drop to 65–70% — most documents remain clearly readable at that level.
Your PDFs stay on your device. The vast majority of PDF compressors — including the most popular free ones — upload your file to a remote server. For a contract, a medical form, or a financial statement, that means sensitive content passes through third-party infrastructure you don't control. This tool processes everything locally using browser APIs. Nothing is transmitted.
You control the quality, not an algorithm. Automatic compressors make assumptions about what level of quality is acceptable. A manual slider means you see the estimated output size and decide exactly where to land — whether you need to hit a specific file size limit or just want the document to load faster in email.
No account, no watermarks, no limits. Many free PDF compressors add a watermark to the output or cap free usage at a few files per day. This tool has none of those restrictions.
How does browser-based PDF compression work?
Each page is rendered to a canvas element, then re-encoded as a compressed JPEG. A new PDF is assembled from those images. This removes embedded fonts, metadata, and redundant structures — producing a smaller file. The quality slider controls the JPEG compression level.
Will the text still be selectable after compression?
No. Pages are stored as images in the output PDF, so text won't be selectable or searchable. If you need to preserve selectable text, use a server-side tool that handles font subsetting. For most sharing and archiving purposes, the image-based output is perfectly readable.
Are my PDF files uploaded to a server?
No. PDF.js renders the pages locally and pdf-lib assembles the output — all inside your browser tab. Your document never leaves your device.
How much can I reduce a PDF's file size?
Scanned documents and image-heavy PDFs can often be reduced by 50–80%. Text-heavy PDFs with vector content may only reduce by 20–40%, since that content re-encodes less efficiently as JPEG images.
What quality setting should I use?
Start at 80%. For documents where precise readability matters (contracts, forms), stay at 80–90%. For drafts or documents where file size matters more than perfect clarity, try 60–70%.
Is there a file size or page limit?
There is no server-side limit. Large PDFs may take longer to process and use more browser memory. Most documents up to 50–100 pages process without issue on a modern device.
Free. Instant. No sign-in. Drop in your PDF and make it smaller.
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