The Arch E1 paper size measures 30 inches wide by 42 inches tall, giving it a very large surface area of 1,260 square inches. Arch E1 was added to the ANSI architectural series as an intermediate size between Arch D and the extra-large Arch E. Its unique 7:5 aspect ratio does not match the other sizes. The 30x42 dimensions provide substantial space for expansive drawings and multi-page layouts. Typical uses include wide architectural site plans, elevation drawings needing more width, and large spreads combining several pages at reduced scale. The ultra-wide shape lends itself to landscape layouts as well. Arch E1's size falls halfway between Arch D and Arch E, filling a niche for projects needing more area than Arch D but significantly less than the monumental Arch E. It also bridges a large step gap that would otherwise exist between the practicality of Arch D and the extreme dimensions of Arch E.