Units of paper quantity Units of paper quantity Various measures of paper quantity have been and are in use. Although there are no S.I. units such as quires and bales, there are ISO and DIN standards for the ream. Expressions used here include U.S. Customary units. A quire of paper is a measure of paper quantity. The usual meaning is 25 sheets of the same size and quality: of a ream of 500 sheets. Quires of 25 sheets are often used for machine-made paper, while quires of 24 sheets are often used for handmade or specialised paper of 480-sheet reams. (As an old UK
Book of Kells sewn together to form gatherings called quires. On occasion, a folio is not part of a bifolio but is instead a single sheet inserted within a quire. The extant folios are gathered into 38 quires. There are between four and twelve folios (two to six bifolios) per quire; the folios are commonly, but not invariably, bound in groups of ten. Some folios are single sheets, as is frequently the case with the important decorated pages. The folios had lines drawn for the text, sometimes on both sides, after the bifolios were folded. Prick marks and guide lines can still be