Portals for jobs, visas and universities still quote 100KB as if it were 2009. Here is a sequence that actually lands under the cap.

  1. Crop PDF to drop scanner borders.
  2. Compress PDF at 0.55. Check the downloaded size in your file manager.
  3. Still heavy? Convert to JPG at 0.5 quality, then JPG to PDF.
  4. One-page forms compress further than 12-page packets — split first with Split PDF.

If the file is already a born-digital letter, it may already be under 100KB. Compression cannot invent a smaller encoding of vector text than the original.

All of this stays on the device. A “100KB compressor” that wants an account is not saving kilobytes; it is saving your email.