About Paperchord
Paperchord is a paper-size reference — 52 sheet and envelope sizes, each drawn on your screen at true physical scale, with pixel dimensions at every print resolution.
The numbers aren't looked up; they're derived. ISO 216 defines paper by one rule — a √2 aspect ratio, halved and rounded down — so this site computes the entire table from the standard's own construction and our build fails if any derived value drifts from the official figures. Inch-defined sizes and envelope standards cite Markus Kuhn's canonical reference (CC BY 4.0) on the page that uses them.
True size on a screen is an honest promise with a caveat: CSS defines an inch as 96 pixels, and real displays deviate a little. That's why every sheet page offers calibration — hold a bank card to the screen once, and every size renders at real physical scale from then on.
Missing a size or a standard worth covering? Email howdy@paperchord.app.