<P> In the mid-1950s , the United States 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 US `` 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 ) . </P>
<P> In the mid-1950s , the United States 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 US `` 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 ) . </P>
when did the king size bed come out
when did the king size bed come out
mid-1950s
mid-1950s