How to compress a PDF file online for free
A large PDF can be too big to email or upload to a portal. Compressing it shrinks the file size while keeping it readable. The steps below use a free browser-based compressor — your file never leaves your device, so even confidential documents stay private.
Open the Compress PDFStep by step
- 1
Open the PDF compressor
Go to the Compress PDF tool. Nothing installs and you do not need an account.
- 2
Add your PDF
Drag your PDF onto the upload area or click “Choose PDF” and pick the file from your device.
- 3
Pick a compression level
Choose a balance between smaller size and quality. “Recommended” works for most documents; use stronger compression for scans and images.
- 4
Download the smaller PDF
Click download. Your compressed PDF saves straight to your device — the original is untouched.
Tips
- Scanned PDFs (image-based) compress the most because images dominate the file size.
- If a PDF is already optimized, the size may only drop a little — that is normal.
- For a target size (e.g. under 100 KB), compress, check the result, and repeat one level stronger if needed.
Frequently asked questions
Does compressing a PDF reduce its quality?
Light compression is visually lossless for text PDFs. Stronger levels reduce image resolution, which can soften scans — pick the lowest level that hits your target size.
Is it safe to compress confidential PDFs here?
Yes. The compression runs entirely in your browser; the file is never uploaded to any server.
Why is my PDF still large after compressing?
PDFs that are already optimized, or that contain high-resolution images you need to keep, have less room to shrink. Try a stronger level or remove unneeded pages first.