Bed sizes vary considerably around the world, with most countries having their own standards and terminology. While the "double" size appears to be standard among English speaking countries, based on the imperial measurement of 4 ft 6 in by 6 ft 3 in (137 cm x 190 cm), the sizes for other bed types tend to vary. The mainland European sizes differ, not merely because of the use of the metric system.[citation needed]
In the mid-1950s the U.S. bedding industry introduced a new size, the king size.
A king-sized bed differs from the other sizes in implementation, as it is not common to have a king-sized box spring; rather, two smaller box-springs are used under a king-sized mattress. It is a common misconception that in a U.S. "standard" or "Eastern king", the box springs are identical in size to a "twin extra-long"; however, "twin extra-long" mattresses next to each other add up to 78 inches (200 cm) wide instead of the 76 inches (190 cm) width that is standard for an "eastern king". Another size variant in the United States is the "California king", which measures 72 by 84 inches (180 cm × 210 cm) long (narrower but longer than the standard king).
What is referred to as a "single bed" in many parts of the world may also be known in U.S. terminology as a "twin bed." In some countries, a "twin bed" may also be used to describe one of two single beds in the same room. As another example, in some cultures, the "full mattress" is referred to as a "master size bed."
When a mattress is available in fixed size (for example, twin or queen), and the description does not specify the exact size, this table may be used.
Mattress size[citation needed]Size in inchesSize in cm
Cot size 30" wide x 74" long76x188
Twin 39" wide x 75" long99x190
Twin extra long 39" wide x 80" long99x203
Full size 54" wide x 75" long137x190
Full extra long 54" wide x 80" long137x203
Queen size 60" wide x 80" long153x203
Cal-king 72" wide x 84" long183x214
King size 76" wide x 80" long193x203
All mattresses are made according to certain standards, but different brands sometimes have exceptions. Most often, the difference is 2-5 inches. When calling a business to check, specify the exact size of the mattress.