Maker disclosure: I built the free PDF compressor at all-done.xyz, including the Compress PDF tool . This post adapts my guide on that site, so you can follow the same method here.

If a job portal, university form, or email system has ever rejected your file for being too large, you know the frustration. The limit is often 1 MB, and the file in question looks harmless — a few pages, some photos, nothing dramatic. Getting under that limit is usually straightforward once you know where the extra megabytes are hiding.

This is a cross-post adapted from my full guide, How to Compress a PDF to 1MB Without Losing Quality .

What makes a PDF so large?

In most cases, it is not the text. A hundred pages of plain text weighs very little.…