PDF to JPG at 300 DPI

Three hundred dots per inch is the resolution print shops and desktop publishing software have used as their baseline for decades, because it sits comfortably above what the human eye can distinguish at typical reading distance from a printed page — going higher rarely improves the visible result but reliably increases file size. Beyond literal printing, this setting is also the right choice for any image destined to be placed inside a layout tool, a presentation, or a document where it might be resized or viewed larger than its original page dimensions, since starting from more pixels gives that later resizing room to work with.

The trade is a straightforwardly larger file than the 150 DPI screen default — often four times the pixel count, since DPI scales area quadratically — which is the right cost to accept when the destination genuinely needs it and the wrong one to pay by default for something that will only ever be viewed on a screen.

Some documents use non-standard page dimensions — oversized architectural drawings or wide spreadsheets exported to PDF, for instance — and rendering an already-large page at 300 DPI multiplies its pixel dimensions further still. Browsers impose a hard ceiling on how large a single canvas can be, so an unusually large page at this resolution is automatically capped to stay within that limit rather than failing outright, which occasionally means a genuinely oversized page renders at slightly less than the full requested DPI.