Sheet pans, baking trays or baking sheets are flat, rectangular metal pans used in an oven

Oven

An oven is a thermally insulated chamber used for the heating, baking or drying of a substance. It is most commonly used for cooking. Kilns, and furnaces are special-purpose ovens...

. They are primarily used for baking

Baking

Baking is the technique of prolonged cooking of food by dry heat acting by convection, and not by radiation, normally in an oven, but also in hot ashes, or on hot stones. It is primarily used for the preparation of bread, cakes, pastries and pies, tarts, quiches, cookies and crackers. Such items...

 flat products such as cookie

Cookie

In the United States and Canada, a cookie is a small, flat, baked treat, usually containing fat, flour, eggs and sugar. In most English-speaking countries outside North America, the most common word for this is biscuit; in many regions both terms are used, while in others the two words have...

s, sheet cake

Sheet cake

A sheet cake is a cake baked in a large, flat rectangular pan such as a sheet pan or a jelly roll pan. These single-layer cakes are almost always frosted, and may be decorated on the flat surface on the top...

s, and swiss roll

Swiss roll

A Swiss roll or jelly roll is a type of sponge cake roll. The thin cake is made of eggs, flour and sugar and baked in a very shallow rectangular baking tray, called a sheet pan. The cake is removed from the pan and spread with jam or buttercream, rolled up, and served in circular slices.The...

s.

These pans, like all bakeware, can be made of a variety of materials, but are primarily aluminum or stainless steel

Stainless steel

In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....

. The most basic sheet pan is literally a sheet of metal. Common additional features that may be found in sheet pans include a lip on one or more edges to prevent food from sliding off, handles to aid in placing the pan into the oven, and removing it again, or an insulated bottom designed to protect delicate food from burning.

Types and sizes

A sheet pan that has a continuous lip around all four sides may be called a jelly roll pan. A pan that has at least one side flat, so that it is easy to slide the baked product off the end, may be called a cookie sheet.

Professional sheet pans used in commercial kitchens typically are made of aluminum, with a (1", 2,5 cm) raised lip around the edge, and come in standard sizes. The full-size sheet pan is 26 by 18 inches, which is too large for most home ovens. A three quarter size sheet pan is 21 by 15 inches. A half sheet pan is 18 by 13 inches. Quarter sheets are 9 by 13 inches. The half sheet is approximately the same size as mass-market baking sheets found in supermarkets, and the quarter sheet is a common size for rectangular, single-layer cakes. Other commercial kitchen equipment, such as cooling racks, ovens, and shelving, is made to fit these standard pans.

Common U.S. Baking Tray Dimension Conventions.
Values are approximate, especially height. Values vary depending on rim size and style.

Conventional Size Name	Width (in)	Depth (in)	Height (in)
Full	26	18	1
Three Quarters	21	15	1
Half	18	13	1
Quarter	9	13	1

Liners and Coatings

Some bakers prefer not to bake directly on a sheet pan, particularly for delicate or sticky pastries. Depending on what is being baked, they may use parchment paper

Parchment paper (baking)

Parchment paper and bakery release paper are cellulose-based papers that are used in baking as a disposable non-stick surface. Both are also called bakery paper.-Parchment paper:...

, waxed paper or aluminum foil as a liner. The Silpat

Silpat

Silpat is the brand name of a silicone mat used in baking and in the production of candy to provide a non-stick surface without fat or parchment paper. Silpats contain a Fiberglass weave that reinforces the silicone...

is a flexible silicone material used as a reusable liner.

Sheet pans may be coated with a glaze to prevent food from sticking to their surface. When purchased with a glaze, sheet pans are often straightened and/or re-coated with a glaze.