How Many? A Dictionary of Units of Measurement |
Data from Markus Kuhn, International Standard Paper Sizes. See this site for a complete discussion of how the ISO 216 paper sizing system works. This system is used in most of the world, replacing traditional paper sheet sizes such as the 8.5 by 11 inch size familiar in the U.S. (See this link for information on the traditional paper sizes.)
In brief, international paper sizes are in three series, designated An, Bn, and Cn. Increasing the number n by 1 halves the area of the sheet, so that, for example, an A5 sheet is an A4 sheet cut in half. The basic sheet A0 has an area of 1 square meter, so an A4 sheet (the standard size for business letters) has an area of 1/16 square meter. The ratio between the height and width of a sheet is always the square root of 2 (about 1.414).
The area of a Bn sheet is the area of the An sheet multiplied by the square root of 2, so a B5 sheet, for example, is intermediate in size between an A4 and an A5 sheet. The Cn size, intended mostly for envelopes, has an area equal to the fourth root of 2 (about 1.189) times the area of the An sheet, which means that an An sheet fits nicely, unfolded, in a Cn envelope.
The dimensions of the sheets are computed from these formulas:
Format |
Width [m] |
Height [m] |
---|---|---|
An |
2^{-1/4-}^{n}^{/2} |
2^{1/4-}^{n}^{/2} |
Bn |
2^{-}^{n}^{/2} |
2^{1/2-}^{n}^{/2} |
Cn |
2^{-1/8-}^{n}^{/2} |
2^{3/8-}^{n}^{/2} |
With roundoff, the dimensions (in millimeters) are as follows:
A Series Formats |
B Series Formats |
C Series Formats |
|||||
---|---|---|---|---|---|---|---|
4A0 |
1682 × 2378 |
- |
- |
- |
- |
||
2A0 |
1189 × 1682 |
- |
- |
- |
- |
||
A0 |
841 × 1189 |
B0 |
1000 × 1414 |
C0 |
917 × 1297 |
||
A1 |
594 × 841 |
B1 |
707 × 1000 |
C1 |
648 × 917 |
||
A2 |
420 × 594 |
B2 |
500 × 707 |
C2 |
458 × 648 |
||
A3 |
297 × 420 |
B3 |
353 × 500 |
C3 |
324 × 458 |
||
A4 |
210 × 297 |
B4 |
250 × 353 |
C4 |
229 × 324 |
||
A5 |
148 × 210 |
B5 |
176 × 250 |
C5 |
162 × 229 |
||
A6 |
105 × 148 |
B6 |
125 × 176 |
C6 |
114 × 162 |
||
A7 |
74 × 105 |
B7 |
88 × 125 |
C7 |
81 × 114 |
||
A8 |
52 × 74 |
B8 |
62 × 88 |
C8 |
57 × 81 |
||
A9 |
37 × 52 |
B9 |
44 × 62 |
C9 |
40 × 57 |
||
A10 |
26 × 37 |
B10 |
31 × 44 |
C10 |
28 × 40 |
Note: To convert the dimensions to inches, divide by 25.4. Thus an A4 sheet measures 8.27 by 11.69 inches, making it a little taller and narrower than an 8.5 by 11 inch sheet.
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You are welcome to email the author (rowlett@email.unc.edu) with comments and suggestions.
All material in this folder is copyright © 2000 by Russ Rowlett and the University of North Carolina at Chapel Hill. Permission is granted for personal use and for use by individual teachers in conducting their own classes. All other rights reserved. You are welcome to make links to this page, but please do not copy the contents of any page in this folder to another site. The material at this site will be updated from time to time.
March 29, 2000