A1.0

The A1.0 is an elongated paper size defined in the ISO 5457 standard. It combines the 594 mm short side of an A1 sheet with the 1189 mm long side of an A0 sheet. This results in the A1.0 having dimensions of 594 mm x 1189 mm. With an aspect ratio of 2:1, the A1.0 is twice as long as it is wide. The total surface area of an A1.0 sheet is 707,666 mm2 or 0.7077 m2.

ISO 5457 introduced these elongated sizes in 1999 to provide more flexibility than the standard A-series paper dimensions. The idea is that the elongated sizes maintain the width-to-length ratios of the standard A-series, so they are compatible and consistent, while offering more choice in paper dimensions. This is useful for technical drawings or designs that need a particular elongated orientation. The A1.0, along with other ISO 5457 sizes, has been adopted for use in the United States by the ANSI/ASME Y14.1 standard alongside the regular A-series and inch-based paper sizes. Overall, the A1.0 format provides a longer dimension than A1 for narrow or extended drawings while keeping the familiar proportions of A-series paper.