# Paper Drafting Sizes - ISO 216 series A, B and C

## The ISO 216 A, B and C drawing series - dimensions of regular, oversized and envelope sheets

ISO 216 "Writing paper and certain classes of printed matter; Trimmed sizes; A and B series" specifies international standard (ISO) paper sizes, used in most countries in the world today with three series of paper sizes: A, B and C. Series C is primarily used for envelopes.

### ISO A Series

The ISO A series of sheet sizes is based on a constant width to length ratio of *1:√2* (rounded to the nearest millimeter). The A0 size is defined as having an area of one square meter *(1 m ^{2})*. Paper weights is expressed in grams per square meter.

Each smaller sheet size is exactly half the area of the previous size.

ISO A Series | Size | |
---|---|---|

(mm) | (inches) | |

A0 | 841 x 1189 | 33.11 x 46.81 |

A1 | 594 x 841 | 23.39 x 33.1 |

A2 | 420 x 594 | 16.54 x 23.29 |

A3 | 297 x 420 | 11.69 x 16.54 |

A4 | 210 x 297 | 8.27 x 11.69 |

A5 | 148 x 210 | 5.83 x 8.27 |

A6 | 105 x 148 | |

A7 | 74 x 105 | |

A8 | 52 x 74 | |

A9 | 37 x 52 | |

A10 | 26 x 37 | |

A11 | 18 x 26 | |

A12 | 13 x 18 |

ISO 216 does not define sizes larger than A0 or B0. With the German standard DIN 476 "Trimmed sizes of paper" the sizes can be expanded by using a factor in front of the size:

- 2A0 is twice the size of A0
- 4A0 is four time the size of A0

### Oversized ISO A Sheets

Oversized sheets are used when it is desirable to give extra protection to the drawing sheets by providing a binding or trimming margin.

ISO A Series | Size(mm) |
---|---|

RA0 | 860 x 1220 |

RA1 | 610 x 860 |

RA2 | 430 x 610 |

RA3 | 305 x 430 |

RA4 | 215 x 305 |

RA5 | 153 x 215 |

### ISO B Series

The ISO B series are geometric means between the A series and defined to satisfy the requirements of sizes between the A series sizes. For example, B1 is a geometric mean between A1 and A0.

ISO B Series | Size | |
---|---|---|

(mm) | (inches) | |

B0 | 1000 x 1414 | 39.37 x 55.67 |

B1 | 707 x 1000 | 27.83 x 39.37 |

B2 | 500 x 707 | 19.68 x 27.83 |

B3 | 353 x 500 | 13.90 x 19.68 |

B4 | 250 x 353 | 9.84 x 13.90 |

B5 | 176 x 250 | 6.93 x 9.84 |

B6 | 125 x 176 | |

B7 | 88 x 125 | |

B8 | 62 x 88 | |

B9 | 44 x 62 | |

B10 | 31 x 44 | |

B11 | 22 x 31 | |

B12 | 15 x 22 |

### ISO C Series - Envelopes

Series C is primarily used for envelopes. The C series formats are geometric means between the B series format with the same number and the A series format with the same number - C2 is the geometric mean between B2 and A2.

ISO C Series Envelopes | Size | |
---|---|---|

(mm) | (inches) | |

C0 | 917 x 1297 | 36.00 x 51.20 |

C1 | 648 x 917 | 25.60 x 36.00 |

C2 | 458 x 648 | 18.00 x 25.60 |

C3 | 324 x 458 | 12.80 x 18.00 |

C4 | 229 x 324 | 9.00 x 12.80 |

C5 | 162 x 229 | 6.40 x 9.0 |

C6 | 114 x 162 | |

C7 | 81 x 114 | |

C8 | 57 x 81 |

An A4 page will fit into a C4 envelope, A5 will fit into a C5 envelope and so on.

### Other Commonly Used Formats

Name | Size (mm) |
---|---|

Letter | 215.9 x 279.4 |

Legal | 215.9 x 355.6 |

Executive | 190.5 x 254.0 |

C5E | 163.0 x 229.0 |

Comm10 | 105.0 x 241.0 |

DLE | 110.0 x 220.0 |

Folio | 210.0 x 330.0 |

Ledger | 432.0 x 279.0 |

Tabloid | 279.0 x 432.0 |