What fits when you compress PDF to 20KB? Our test
On 2026-11-13 we made five one-page test files built to look like scans at 200 DPI (apart from the typed letter) and compressed each against a 20 KB target, once at Recommended and once at Smallest (table below). Two came in under the limit. A scan of an ID card, cropped to the card itself, fitted at both levels: 13.1 KB at Recommended and 18.3 KB at Smallest. Smallest came out larger because the tool keeps the first resolution step that fits, which here was its sharpest one, not the smallest it could reach. A full A4 page of black text on white paper fitted only at Smallest, at 19.2 KB, with little to spare.
The other three stayed over at both levels: a colour A4 scan (44.2 KB at best), an A4 record with a passport-size photo on it (34.1 KB) and, perhaps unexpectedly, a typed one-page letter saved as PDF from a browser (21.9 KB). Smallest stops at 72 DPI and JPEG quality 30 out of 100, where an A4 page still has about half a million pixels to describe in 20,000 bytes; colour, photos and crisp lettering use that up first. Your files will come out differently, but a full colour page is unlikely to fit in a 20 KB PDF.
