How to compress a PDF (and actually make it smaller)
What makes a PDF heavy, how to pick the right compression level and what to try when the file refuses to shrink.
Skip the reading. Use Compress PDF.Shrink it until the email goes through. Free, no sign-up, nothing uploaded.→The short version
- Open Compress PDF and drop in your file.
- Choose Recommended unless you have a reason not to.
- Check the before and after size, then download.
- Still too big? Go back and try Strong.
Why is my PDF so big?
Text costs almost nothing. A 200-page novel can be under 1 MB. Size almost always comes from images: scanned pages, photos taken on a phone, or slides exported at print resolution. A single uncompressed scan can be 5–10 MB on its own.
- Scans saved as images at 300–600 DPI.
- Phone photos dropped into a document at full resolution.
- Embedded fonts, especially several large ones.
- Leftover data from editing software, like duplicate objects and old revisions.
Choosing a compression level
Light keeps images close to their original quality and is the safe choice for documents you'll print. Recommended is tuned for on-screen reading and email, which is where most PDFs end up. Strong trades visible quality for the smallest possible file, which is useful when a portal has a hard 2 MB limit.
Text-heavy document? Look at the result screen. If it says pages were redrawn as images, the text is no longer selectable. Try Light, or keep the original if searchable text matters.
When the file won't get smaller
If a PDF is mostly text and was exported well, it's already close to its minimum size. Compression can't remove what isn't there. In that case, split the document and send only the pages that matter, or share a link instead of an attachment.