basis weight

measurement

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June 22, 2026

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Basis weight is a fundamental measurement in papermaking that quantifies the weight of a sheet of paper. It is typically defined as the weight in pounds of a 500-sheet ream of paper cut to a basic size. This measurement is also referred to as basic weight or substance number.12

To determine basis weight, paper samples are conditioned under standard temperature and humidity. The properties of paper can change with moisture content, so tests are conducted under controlled conditions. This measurement is crucial for identifying and expressing differences in paper varieties, which are used in a wide range of applications.1

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papermaking
Substance and quantity measurement
…substance per unit area, called basis weight, is a fundamental property of paper and paperboard products. From the first uses of paper in the printing trades, it has been measured in reams, originally 480 sheets (20 quires) but now more commonly 500 sheets (long reams). The term ream weight commonly…
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…substance per unit area, called basis weight, is a fundamental property of paper and paperboard products. From the first uses of paper in the printing trades, it has been measured in reams, originally 480 sheets (20 quires) but now more commonly 500 sheets (long reams). The term ream weight commonly…
Read More