Storage Capacity of the database nvarchar

Only one byte is required for English characters, but many Chinese characters require two bytes for storage.
When I was designing a database, I used nvarchar (n) for character storage. I did not know much about it, I always thought that I could store 2/n Chinese characters and n English characters. But tell me at the same time today-in fact, the English characters are the same as the Chinese characters, both of which are n.
It turns out that nchar, nvarchar, and ntext are separated by the letter "N", indicating that they are characters of the Unicode data type. Unicode Character Set is generated to solve the incompatibility problem of character sets. All its characters are expressed in two bytes, that is, English characters are also expressed in two bytes. The length of nchar and nvarchar is between 1 and 4000. Compared with Char and varchar, nchar and nvarchar can store up to 4000 characters, whether in English or Chinese. Char and varchar can store up to 8000 English and 4000 Chinese characters. It can be seen that when using nchar and nvarchar data types, you do not have to worry about whether the entered characters are English or Chinese characters, which is more convenient, but there is some loss in the amount of stored English hours.