A4
210 × 297 mm · ISO 216
By sheet
Pick the paper your printer (or plotter) actually owns
Every grid in the library is rendered against both the ISO A-series and the ANSI/US loose family, so you can print a 1:50 plan on A3 in Berlin or 11×17 in Brooklyn and trust that the proportions survive.
A3
297 × 420 mm · ISO 216
A2
420 × 594 mm · ISO 216
Letter
216 × 279 mm · ANSI A
Legal
216 × 356 mm · US Loose
Tabloid
279 × 432 mm · ANSI B
The two systems, side by side
The international ISO 216 paper system - A4, A3, A2 and so on - is built around the elegant property that each successive size doubles the area of the last while keeping the same aspect ratio of √2:1. That's why an A3 sheet folds neatly into two A4s, and why architectural plan series scale predictably.
The North American loose family - Letter (8.5×11"), Legal (8.5×14") and Tabloid (11×17") - predates ISO 216 by decades and remains the everyday office stock in the United States and Canada. Craft Grids renders every grid in both families so you don't have to choose.