<P> 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 . </P> <Dl> <Dt> Writing paper measurements </Dt> <Dd> 25 sheets = 1 quire </Dd> <Dd> 500 sheets = 20 quires = 1 ream </Dd> <Dd> 1,000 sheets = 40 quires = 2 reams = 1 bundle </Dd> </Dl>

A bundle of pieces of paper is called