PDF Compressor
Reduce the file size of scanned or image-heavy PDFs — entirely in your browser. Nothing is uploaded to a server.
How it works: each page is re-rendered at an optimized resolution and re-encoded as a compressed image, then rebuilt into a new PDF. This works best on scanned documents, photos, and image-heavy PDFs. Note: text in the output is no longer selectable, since pages are flattened to images.
How to Compress a PDF
- Click the upload area and choose (or drag) the PDF you want to shrink.
- Pick a compression level — High compression for the smallest file, Balanced for a good mix of size and quality, or Low compression to keep quality closer to the original.
- Click "Compress PDF" and watch the status message as it works through each page.
- Review the Original Size, Compressed Size, and Saved percentage in the stats, then click "Download Compressed PDF".
Frequently Asked Questions
Why is my compressed PDF still large, or barely smaller?
This tool works by re-rendering each page as an image and re-encoding it — it shines on scanned documents and photo-heavy PDFs. If your PDF is mostly vector text (like a Word export), it's often already compact, so the savings can be small; the status message will say "already well optimized" when that happens.
Will the text in my PDF still be selectable or searchable after compressing?
No. Compression flattens every page into a JPEG image and rebuilds the PDF from those images, so any selectable text becomes part of a picture and can no longer be copied or searched. If you need to keep searchable text, skip compression or extract the text first with the PDF to Text tool.
What's the difference between High, Balanced, and Low compression?
High compression renders pages at the lowest resolution and JPEG quality for the smallest possible file; Balanced is a middle ground recommended for most documents; Low compression renders at higher resolution and quality, keeping the file closer to the original size but sharper.
Is there a file size limit?
The dropzone recommends a maximum of 50 MB. Larger files can still work, but very large or very long PDFs may take a while, or run into your browser's memory limits, since every page is rendered and re-encoded locally on your device.
Does the compressor upload my file anywhere?
No. Everything — reading the PDF, rendering pages, re-encoding, and rebuilding the file — happens locally in your browser using pdf.js and pdf-lib; your document never leaves your device.