SQL Server - what is the size of nchar(10) and nvarchar(10)

difference between nchar(10) and nvarchaer(10)

char is fixed at 10.  Good if the value will always be the max length.

varchar varies up to 10 (contains extra byte or two to track actual storage)

nchar and nvarchar are the same.  The distinction is that they have storage for various international language characters.