Units of paper quantity was ordered by the ream of 480 sheets. In 1840, a ream in Lisbon was 17 quires and 3 sheets = 428 sheets, and a double ream was 18 quires and 2 sheets = 434 sheets; and in Bremen, blotting or packing paper was sold in reams of 300 (20 quires of 15 sheets). A mid-19th century Milanese-Italian dictionary has an example for a "risma" (ream) as being either 450 or 480 sheets. In the UK in 1914, paper was sold using the following reams: Reams of 500 sheets were mostly used only for newsprint. Since the late 20th century,
Paper × 841 mm). A1 is half the size of a sheet of A0 (i.e., 594 mm × 841 mm), such that two sheets of A1 placed side by side are equal to one sheet of A0. A2 is half the size of a sheet of A1, and so forth. Common sizes used in the office and the home are A4 and A3 (A3 is the size of two A4 sheets). The density of paper ranges from for tissue paper to for some speciality paper. Printing paper is about . Paper may be classified into seven categories: Some paper types include: