Paper Bulk (Specific Volume)
Compute the bulk (apparent specific volume) of paper, bulk = thickness (µm) / grammage (g/m²), in cm³/g, the inverse of density. A high bulk means a 'fluffier', more voluminous paper for the same weight (book papers, boards, tissue), giving stiffness and softness; a low bulk gives dense, thin paper (high-quality printing papers, glassine). It is a key paper-design parameter. Enter the thickness and the grammage.
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Paper bulk (specific volume)
The bulk = thickness (µm) / grammage (g/m²), in cm³/g, is the apparent specific volume of paper — the inverse of its density. It measures how fluffy or how dense a sheet is at the same weight. A high bulk means paper that is voluminous, full bodied and light all at once, with plenty of air between the fibers — desirable in books (a chunky novel makes a better impression on the shelf, and the reader feels the heft and the value; hence the special bulky grades made for it), boards and packaging (stiffness at low weight) and tissue papers (the softness and absorbency of toilet paper come from the trapped air). A low bulk gives a dense, thin and smooth sheet — high quality printing grades (coated), banknote paper, glassine (translucent), where density brings smoothness, controlled opacity and good image reproduction. Bulk is tuned by fiber refining (more refining leads to more flexible, denser fibers and less bulk), by calendering (pressing between rolls smooths and densifies, cutting bulk and caliper) and by fiber choice (stiff softwood fibers give more bulk). It ranks among the first design targets of any new paper grade. Enter the thickness and the grammage.
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The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.