How is the watch size expressed? The dimension of a round case is expressed in diameter (usually without crown). The dimension of a square or barrel watch is given in width and length. The unit of size is usually millimeter (mm).
The typical sizes of domestic men's watches are 38mm and 40mm. With the popularity of large watches in recent years, the size of watches is more than 40 mm, such as 42 mm, 43 mm, the maximum is 47 mm. The typical size of domestic women's watches is 28 mm. In recent years, it has become fashionable for women to wear large-sized watches, so more and more watches are about 38mm in size.
Generally speaking, formal watches should be bought properly, rather small than large. Others, on the contrary, prefer big to small.