Why is my PDF so large?
Text is tiny. A hundred pages of plain text is only a few hundred kilobytes. When a PDF is many megabytes it is almost always because of images: a phone photo dropped in at full resolution, or a scanned document where every page is a large picture.
That's good news, because images can be re-encoded at lower quality and the file shrinks dramatically while still looking fine on screen.
Two ways to compress a PDF
Which method is right depends on what your PDF contains:
- Smart compression re-encodes only the images inside the PDF and leaves text and vector graphics alone. Your document stays searchable and the text stays sharp. Use this for documents that mix text and pictures.
- Flatten compression turns every page into a single image. It can shrink almost anything, but the text is no longer selectable. Use this for scans, where every page is already just a picture.
How to hit a specific size like 1 MB or 2 MB
Many portals and email systems have a hard limit — 1 MB, 2 MB, 5 MB. Instead of guessing a quality setting, pick a target size. The tool tries progressively stronger compression until the file fits, and tells you honestly if it couldn't quite get there. That is much faster than repeatedly trying settings yourself.
What if it didn't shrink much?
If a PDF is mostly text it is already small, and there is little to gain. A PDF that was already carefully optimised may also barely change. In those cases, splitting the document into two parts and sending them separately is often the practical answer.
Keep a copy of the original
Compression is lossy for images, so keep your original file. Send the compressed copy and archive the full-quality one.