Compress PDF
Shrink a PDF for email or upload portals. The result tells you exactly how many bytes were saved — or that the file was already as small as it gets.
About Compress PDF
Compress PDF makes a PDF smaller so it fits an email attachment or an upload form. Choose Light, Recommended or Strong compression, and optionally convert colours to grey for scanned documents.
When it finishes it shows exactly how many bytes were saved, and says so honestly if the file was already as small as it can get.
When to use Compress PDF
- Fit a document under the 10 MB or 25 MB limit of an email service.
- Meet the size limit of a job, visa or university application portal.
- Make a large scan quicker to download and share.
Tips for the best result
- Start with Recommended: it balances size and clarity for most files.
- Use Strong only if the file is still too big, and check the pictures afterwards.
- Turn on grey conversion for black-and-white scans: it can save a lot, but it removes colour.
- A PDF made mostly of text will not shrink much, because there is little to compress.
How to use Compress PDF online
- 1
Upload your file
Choose a PDF file or drag and drop it onto the page.
- 2
Choose your options
Adjust the settings if you need to, or keep the sensible defaults.
- 3
Run Compress PDF
Click the button and the file is processed on our secure server in seconds.
- 4
Download the result
Download your new file. Your upload and the result are deleted automatically afterwards.
Read the full guide: How to Compress a PDF and Reduce File Size (Without Losing Quality) →
Frequently asked questions
Will compressing reduce the quality?
Compression mainly reduces the size of images inside the PDF. Light keeps them nearly the same, while Strong trades some sharpness for a much smaller file. Text stays sharp.
Why did my file not get smaller?
Some PDFs are already optimised, or contain mostly text, so there is nothing left to squeeze. The result page tells you when this happens.
Is Compress PDF free?
Yes. You can use Compress PDF on SnapPDF for free, without creating an account. Paid plans only raise the limits for heavy use.
How do I use Compress PDF?
1. Upload your file. 2. Choose your options. 3. Run Compress PDF. 4. Download the result.
Are my files safe?
Yes. Files are sent over HTTPS, stored encrypted, visible only to you, and deleted automatically after processing. We never sell your files or use them to train AI.
Do I need to install any software?
No. Compress PDF works in any modern browser on Windows, Mac, Linux, Android and iPhone.
Which file types are supported?
Compress PDF accepts PDF files.
What else can I do with SnapPDF?
SnapPDF has more optimize pdf tools and many others to merge, split, compress, convert, edit and secure PDFs.