Is 1 MB small enough for email?

Yes. Most email services accept attachments of 20–25 MB, so 1 MB sends quickly and won't fill the recipient's inbox.

Why is my 10 MB PDF only a little smaller?

This tool shrinks embedded JPEG photos. If the size comes from fonts, vector drawings or PNG images, it can't reduce it much. You can convert pages to images with PDF to JPG and rebuild with JPG to PDF, but the text will no longer be selectable.

Compress PDF to 1 MB