How to Compress a PDF Online
1. Upload your PDF
Drag it into the box above or click Browse. You can queue multiple files and compress them in the same batch.
2. Choose Basic or Strong
Basic for minimal visible change, Strong for a smaller file at some cost to image sharpness.
3. Download your compressed PDF
Text, fonts, and layout are unchanged; only file size (and, at Strong, image sharpness) is affected.
What to Know Before You Compress
Text and fonts are untouched
Compression works on images and redundant internal data. Your words, fonts, and layout come through exactly as they went in.
Image quality depends on the level
Basic is close to lossless. Strong is visibly more aggressive on image-heavy pages (scanned documents, photo-heavy reports) and barely noticeable on text-only ones.
No file size limit
Large scanned PDFs compress the same way as short text documents.
Works anywhere
Runs in the browser on any device, desktop or mobile, with nothing to install.
If your PDF is password-protected, you'll need to remove that first with Unlock PDF before this tool can compress it.
Common Reasons to Compress a PDF
Email attachment limits
Gmail and Outlook cap attachments around 20-25MB. A scanned PDF can blow past that easily; compression is often the fastest fix.
Upload portals with a size cap
Job applications, government forms, and university portals frequently reject anything over a few MB, regardless of how good the reason for the file being large is.
Faster sharing and loading
A smaller file uploads faster to cloud storage and opens faster for whoever you send it to, especially on a slow connection.
Works anywhere
Runs in the browser on any device, desktop or mobile, with nothing to install.
Storage
A folder of scanned documents adds up fast; compressing before archiving keeps it manageable.
Compress PDF, or Something Else?
f you only need certain pages out of a long document rather than the whole thing smaller, Split PDF will usually get you a smaller file more directly than compressing everything. And if you don't need the PDF to look like a PDF at all, just the words in it, PDF to Textproduces a file that's a fraction of the size of even a heavily compressed PDF, since it drops the images and layout entirely.
What People Do Next
Compressing is often one step in a larger cleanup. If you have several PDFs to combine into one smaller file, Merge PDF can do that before or after compression. If the file needs to end up as an editable document, PDF to Word converts it, and it handles scanned pages via OCR too. And if the PDF is locked, Unlock PDF removes a password you already know.
FAQs
Is Compress PDF free to use?
Yes, with no sign-up and no limit on how many files you compress.
Will compression affect my fonts or text?
No. Text, fonts, and layout stay exactly as they are. Compression works on the file's images and redundant internal data, not the text itself.
Will my PDF lose visual quality?
It depends on the level you choose. Basic compression targets redundant data and typically has little to no visible effect. Strong compression re-encodes images more aggressively for a smaller file, which can be visibly softer on image-heavy pages. If a PDF is mostly text, the difference between the two is usually hard to notice.
Is there a file size limit?
No. Large files compress the same way as small ones.
Can I compress a PDF to an exact target size, like under 5MB?
Not directly. You choose between Basic and Strong rather than a specific target size in MB. If Strong still isn't small enough, splitting the PDF and sharing only the pages you need will usually get you further than compression alone.
Is my uploaded PDF safe and private?
It's uploaded over an encrypted (TLS) connection, processed on our server, and deleted automatically within about an hour. We don't keep a copy after that.
What's the difference between Basic and Strong compression?
Basic aims for a smaller file with minimal visible change, a safe default for documents you'll print or share professionally. Strong pushes the file size down further and is a better fit when the priority is squeezing the file size down (for an email attachment limit, for example) rather than preserving maximum image sharpness.
Why is my PDF so large in the first place?
Almost always it's the images: high-resolution scans, photos, or screenshots embedded at full size. A text-only PDF is rarely more than a few hundred KB; a scanned PDF can run into tens of megabytes for the same page count.
Can I compress multiple PDFs at once?
Yes, you can queue several files and compress them together in the same batch instead of one at a time.
How much smaller will my PDF actually get?
It depends on the file. In one of our own tests, a 10MB scanned PDF compressed down to 131KB (over 98% smaller) with no visible loss in quality. Image-heavy PDFs tend to shrink the most; a mostly-text PDF has less to compress in the first place.
Can I compress a PDF on my phone?
Yes. It runs in any mobile browser, with no app to install.
Do I need to sign up or install anything?
No. Upload, compress, and download, all in the browser.
