If you have a double DIN head unit, the front face plate will be the same width but twice as tall. Since "2 DIN car stereo" is a colloquial term for double DIN, the head unit in your car will measure roughly 7 x 4 inches (180 x 100mm) if it conforms to that standard. read more
In the world of aftermarket car stereos, din is the term used to describe the size of the stereo -- specifically the height. Single-din stereos are the thinnest and measure 2 1/8 by 7 1/8 inches. Double-din is equivalent to two single-din units stacked on top of each other and 1.5 din is right in the middle. read more