Compress PDF
Reduce PDF file size online for free — 100% private, your file never leaves your browser. Great for scanned documents.
Free · No sign-up▶ Watch: How to compress a PDF (0:38)
Video transcript
- Pick a quality. Recommended keeps text sharp and still cuts the size a lot.
- Scanned file? Tick Flatten. For scans, flatten the pages to images to get the smallest file.
- Add your PDF. Drop your PDF in the box or click to browse. It never leaves your device.
- Check the new size. The result shows the old size, the new size and how much smaller the file is.
- Download your PDF. Save the smaller copy. Your original file is not changed.
How to use Compress PDF
- 1. Pick a Quality level: Strong (smallest), Recommended or Light (best quality). Tick Flatten pages to images for scanned documents.
- 2. Drop a PDF into the upload box or click to choose one. A progress bar shows each image or page as it’s processed.
- 3. Review the result card showing the original size, new size and percentage saved, or a note if the PDF is already well-optimized.
- 4. Click the download button to save the file with “-compressed” added to its name. Try a stronger level if it’s still too big.
💡 Tip: Compression works best on scanned or image-heavy PDFs. Text-only PDFs are often already as small as they can be.
Frequently asked questions
Is Compress PDF free, and is there a file size limit?
It’s free, needs no sign-up and adds no watermark. There’s no fixed size limit because the PDF is processed on your device, but very large files depend on your browser’s memory. It handles one PDF at a time.
Is my PDF uploaded when I compress it?
No. The PDF is opened and rewritten in your browser with pdf-lib and PDF.js, and the compressed file is created on your device. Nothing is sent to a server, so it’s safe for bank statements, contracts and ID documents.
How do I compress a PDF without losing text quality?
Leave Flatten unticked. In the default mode, only the JPEG photos inside the PDF are resized and re-compressed; text, fonts, links and forms stay untouched and selectable. Recommended caps photos at 2,000 pixels, while Light keeps more detail.
How do I make a scanned PDF smaller for email?
Tick Flatten pages to images and choose Strong or Recommended. Each page is re-rendered as a compressed JPEG, which usually shrinks scans the most. The trade-off is that text becomes part of the image and is no longer selectable or searchable.
Why didn’t my PDF get smaller?
Compression mainly shrinks large photos. If a PDF is mostly text or vector graphics, or its images are already compressed, there’s little to remove, and the tool tells you the original is already the best version. For scans, try Flatten pages to images.
Will a compressed PDF still open in Adobe Reader and other apps?
Yes. The output is a standard PDF that opens in Adobe Acrobat Reader, Preview on Mac, web browsers and mobile PDF viewers. Password-protected or damaged PDFs can’t be compressed and will show an error instead.