Units of Paper Quantity - Quire

A quire of paper is a measure of paper quantity. The usual meaning is 25 sheets of the same size and quality; 1/20 of a ream of 500 sheets. Quires of 25 sheets are often used for machine-made paper, while 24 sheets are often used for handmade or specialised paper of 480-sheet reams. Quires of 15, 18 or 20 sheets have also been used, depending on the type of paper.