US Sizes

In the United States, the standard mattress sizes are (the people in the drawings are 6 feet tall):

Type of mattress Usual dimensions
cot 30* 75
drawing of person on twin mattresstwin 39 75 or 76
drawing of person on long twin mattresslong twin 39 80
drawing of two persons on double mattressfull or
54 75 or 76
drawing of person on queen mattressqueen 60 80
drawing of person on king mattressking 78 or 79 80
drawing of person on California king mattressCalifornia
72 84

*Cots for adults, which vary widely. Many folding cots are only 26 inches wide, and cot mattresses range from 26 to 38 inches wide.

European sizes

Mattresses are currently 200 centimeters (78.7 inches) long and are offered in various widths: 80, 90, 100, 140, 160, 170, 180 and 200 centimeters.

In the UK, sizes are available to fit older beds that were sized in imperial units, i.e. 3 feet (91.5 × 190 cm) and 4½ feet, a full or double bed (137 × 190).

A “cot” in Europe is a post-crib size for older children, 60×120 cm.

Verbal descriptions

Phrases such as “extra firm,” “firm” and so on may help in comparing different mattresses within a line, but they have no meaning in comparing mattresses from different manufacturers.

In general, mattresses and box springs should be more than 6 inches thick.


The gauge of the wire from which the coils are made is also significant; 13-gauge springs are sturdier than 16-gauge.


A foam mattress should have a density of more than two pounds per cubic foot.

Trying out a mattress

The top of a mattress should be about 18 inches above the floor. In a bunk bed, the top of the lower mattress should be at least 30 inches below the bottom of the upper mattress.


Modern mattresses don't fit old beds (see History, below). Some suppliers, however, specialize in fitting older beds. For example:



In 1922, the Bureau of Standards held a conference of bed and mattress manufacturers. A preliminary study had shown that mattresses were being made in lengths from 6′ to 6′5″ and in widths from 3′ to 4′6″, “odd” widths and lengths “not given.” “By unanimous vote all odd sizes and types of metal and wooden beds were eliminated and four widths and one standard length were adopted, with springs and mattresses to conform therewith.” The four sizes, all 73 inches long, were:

“Full”, the top surface to be 52 inches wide.

4′0″, the top surface to be 46 inches wide.

3′3″, or “twin”, the top surface to be 37 inches wide.

3′0″, the top surface to be 34 inches wide.

Current mattresses are at least 2 inches longer, and the full and twin are 2 inches wider. Between 1960 and 2002, the average height of male Americans ages 20-74 increased from 5′8″ to 5′9½″. The increase since 1922 must be even greater, hence longer mattresses.

The recommendation is in

United States Department of Commerce.
Simplified Practice Recommendation No. 2.
Bedsteads, Springs and Mattresses.

Issued by the Bureau of Standards November 25, 1922.
Washington: Gov't Printing Office, 1922.

Men's average heights are from PHS 2005-1250.


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