Compress a PDF to 100 KB

100 KB is a tight cap, usually found on older government portals that accept a scanned certificate or a single-page form.

A one or two page scan can usually get there, though the result will look coarse. A long document almost certainly cannot — splitting it first is the practical route.

Expect the bottom of the ladder — 72 or 96 DPI — for anything longer than a couple of pages. Body text stays readable on screen, small print blurs, and any photographs show visible blocking. This is a size for clearing an upload limit, not for printing.

Each page is re-rendered as an image at a chosen resolution and quality, then rebuilt into a new PDF. If the result is too big, the tool steps down to a lower setting and tries again, jumping further when it is a long way over. It stops at 72 DPI, below which body text stops being readable.

Send fewer pages. 100 KB is roughly a two- or three-page budget for a scan, so the reliable fix is to extract only the pages the form actually asks for, or split the document and upload it in parts. If it is a text PDF rather than a scan it may already be near its floor, in which case compressing it further mostly costs legibility.

No. This method turns each page into an image, so text becomes part of the picture. That is the trade that makes large scans shrink dramatically. If you need selectable text and your PDF is mostly text already, it is probably close to its minimum size and compressing it will not help much.