In North America king-size beds typically measure 76 x 80 inches. This measurement is standard for king-size mattresses, while beds frames vary in size depending on the style and ornamentation being used.
A king-size mattress measures the same in length as a queen, but is 16 inches wider. King-size beds come in different sizes in other parts of the world. In the United Kingdom, a king measures 59 x 79 inches while those in Japan are 67 x 77. While beds can be custom made to any size, the largest standard size is the Super King which is over 8 feet long by 6.5 feet wide.