When introduced in the New York City subway system, subway tiles were 3-by-6 inches. The standard size of the tile, representing the vast majority of its use still to this day, is 3-by-6. This modular size highlights bathroom shower and tub walls, bathroom backsplashes, kitchen backsplashes and, of course, subway tunnel walls. The subway tiles are both ceramic and glass.
Tile manufacturers also produce small, modular-size subway tile. Multicolored, glass-bodied subway tiles are decorative liners or backsplash materials. Small modular ceramic tile subway tiles are highlighting details or backsplashes and fireplace surrounds. Miniature-size subway tiles are 1-by-3, 1-by-4, 1-by-2 and extra-thin 1/2-by-1-inch pieces.
Although not seen nearly as frequently as their 3-by-6 cousins, subway tiles are available in a 4-by-12-inch size. This larger size is frequently a standalone field tile in backsplashes and bathroom tub/shower surrounds.
Glass mosaic subway tile is more delicate than ceramic subway tile, often requiring different maintenance techniques. Both tiles require a pH-neutral soap cleaning and a special tile-penetrating sealant. A regular application of sealant and maintained cleaning pays off, adding to the longevity of all subway tiles. Consult manufacturer's directions for proper cleaning techniques.