The ISO 217:2013 standard defines the RA and SRA paper formats.

Overview

These paper series are untrimmed raw paper. RA stands for “raw format A” and SRA stands for “supplementary raw format A”. The RA and SRA formats are slightly larger than the corresponding A series formats. This allows bleed (ink to the edge) on printed material that will be later cut down to size. These paper sheets will after printing and binding be cut to match the A format. * The ISO A0 format has an area of 1.00 m² * The ISO RA0 format has an area of 1.05 m² * The ISO SRA0 format has an area of 1.15 m²

Tolerances

Paper in the RA and SRA series format is intended to have a

1:\sqrt

aspect ratio but the dimensions of the start format have been rounded to whole centimetres. For example, the RA0 format has been rounded to 860 mm × 1220 mm from the theoretical dimensions

\sqrt\cdot2^ \mathrm \times \sqrt\cdot2^ \mathrm \approx 861.7 \mathrm \times 1218.6 \mathrm

. The resulting real ratios are: *

43:61 \approx 1:1.4186

for RA0, RA2, RA4; *

61:86 \approx 1:1.4098

for RA1, RA3; *

45:64 \approx 1:1.4222

for SRA0, SRA2, SRA4; *

32:45 = 1:1.40625

for SRA1, SRA3. The sizes of the RA series are also slightly larger than corresponding inch-based US sizes specified in ANSI/ASME Y14.1, e.g. RA4 is roughly equivalent to 8½ in × 12 in and ANSI A (alias ''US Letter'') is defined as 8½ in × 11 in.

Other ISO paper standards

ISO 216 ISO 216 is an international standard for paper sizes, used around the world except in North America and parts of Latin America. The standard defines the "A", "B" and "C" series of paper sizes, including A4, the most commonly available paper si ...

:1975, defines two series of paper sizes: A and B *

ISO 269 An envelope is a common packaging item, usually made of thin, flat material. It is designed to contain a flat object, such as a letter or card. Traditional envelopes are made from sheets of paper cut to one of three shapes: a rhombus, a sho ...

:1985, defines a C series for envelopes

External links

International standard paper sizes
ISO 216 details and rationale

{{ISO standards #00217 Stationery Metrication