Short answer
A full sheet pan measures about 18 by 26 inches. A half sheet is about 18 by 13 inches and a quarter sheet about 9 by 13 inches. Full sheets fit full-size commercial ovens and racks but not most home ovens, while half-size convection ovens take half sheets.
Sizes are nominal and vary slightly between makers, so check the oven and rack specifications if the fit is tight. Pans are usually listed by their outside dimensions, and the flat baking surface is smaller.
Aluminum is widely used because it heats evenly. Heavier gauges resist warping, and a wire-reinforced rim helps a pan hold its shape through hot ovens and repeated washing.
Sheet pans, also sold as bun pans, are used for baking, roasting, holding and transport, and they slide into standard sheet pan racks.
Updated · By Norpex