ISO paper sizes (plus rounded inch values)
| Format | B series | |
|---|---|---|
| Size | mm × mm | in × in |
| 0 | 1000 × 1414 | 39.4 × 55.7 |
| 1 | 707 × 1000 | 27.8 × 39.4 |
| 2 | 500 × 707 | 19.7 × 27.8 |
| 3 | 353 × 500 | 13.9 × 19.7 |
| 4 | 250 × 353 | 9.8 × 13.9 |
| 5 | 176 × 250 | 6.9 × 9.8 |
| 6 | 125 × 176 | 4.9 × 6.9 |
| 7 | 88 × 125 | 3.5 × 4.9 |
| 8 | 62 × 88 | 2.4 × 3.5 |
| 9 | 44 × 62 | 1.7 × 2.4 |
| 10 | 31 × 44 | 1.2 × 1.7 |
There is also the much less common B series. The area of B series sheets is the geometric mean of successive A series sheets. So, B1 is between A0 and A1 in size, with an area of 0.71 m² (√0.5). As a result, B0 has one side 1-metre long, and other sizes in the B series have one side that is a half, quarter or eighth of a metre. While less common in office use, it is used for a variety of special situations. Many posters use B-series paper or a close approximation, such as 50 cm×70 cm; B5 is a relatively common choice for books. The B series is also used for envelopes and passports.