How many characters can be mapped with Unicode?

Question

I am asking for the count of all the possible valid combinations in Unicode with explanation. I know a char can be encoded as 1,2,3 or 4 bytes. I also don\'t understand why

Answer 1

Unicode supports 1,114,112 code points. There are 2048 surrogate code point, giving 1,112,064 scalar values. Of these, there are 66 non-characters, leading to 1,111,998 possible encoded characters (unless I made a calculation error).