Antonio writes: A King size bed is the same as 2-twins pushed together: The box-spring on which the king-size mattress rests often consists of two twin-bed box springs. The U.S. twin size are a little bigger (39" or 1.0m) so the U.S. King size is just about 2.0m. A U.S. Queen-size mattress is 61" wide (1.55m). I just measured a Queen-size mattress in a bedroom in my house. As with everything else, sizes may vary slightly depending on Manufacturer.