printer's ream

A printer's ream is a bundle of 516 sheets of paper, made up of 24 quires. (A quire is 24 sheets, so 24 multiplied by 21.5 equals 516.) This is distinct from a commercial ream, which contains only 500 sheets, and from a ream of writing paper historically measured at 480 sheets. The printer's ream emerged as the standard unit for ordering and invoicing paper in the printing trades from at least the nineteenth century onward.

The extra 16 sheets beyond the round 500 served a practical purpose: they compensated for waste, damage, and spoilage during printing, binding, and finishing operations. When a printer ordered paper by the ream, the extra allowance meant that a job could absorb typical losses and still deliver the contracted number of finished sheets to the customer without requiring a second supply order or partial recount.

Why the odd number matters

The fractional quire (0.5 quires equals 12 sheets) in a printer's ream reflects real workshop conditions. Spoilage rates varied by paper grade, press type, and job complexity, but losses of 2 to 4 percent were routine. By building this loss into the standard unit, both printer and supplier avoided disputes over whether shortages were accidental or deliberate shortchanging. The measure also aligned neatly with book signatures: a 24-page signature printed on both sides of a sheet fit naturally within the accounting logic of quires and reams.

The term has become dated in modern printing because standardized paper grades are now supplied in metric weights (grams per square meter) and in bulk quantities ordered by weight or ream count rather than by the historical quire system. Digital prepress workflow and waste projections computed by software have replaced the rule-of-thumb 3 percent buffer. However, older contracts, inventory records, and trade documents still reference the printer's ream, making familiarity with the unit essential for anyone working with legacy paper stocks or historical print production data.