Mass Specification
Total weight of a fixed area of paper or board measured under controlled environmental conditions. The metric system defines basis weight as grams per square meter, while North American markets use pounds per ream. This measurement accounts for fibres, coatings, fillers and moisture present in the finished substrate.
Commercial Pricing
Transactional costs in the paper industry are usually calculated using the mass of the material delivered. Since basis weight determines the total tonnage of an order, small fluctuations in this value impact the final invoice. Sourcing teams use this figure to compare the cost efficiency of different grades.
A lighter sheet that provides the same thickness as a heavier one offers a yield advantage.
Production Tolerance
Machine stability during the manufacturing process ensures the consistency of the sheet across its entire width. If the basis weight varies beyond the agreed limit, the substrate may cause feeding errors on high speed printing presses. Modern mills use automated scanners to monitor these levels in real time.
Standard industry tolerances are typically within plus or minus five percent of the nominal value. Large deviations can lead to uneven tension in web-fed operations or inconsistent folding resistance in carton production.