The script I wrote :-
declare @str1 as nvarchar(max) = 'b'
, @count as int = 0
while @count<30
BEGIN
set @str1 = @str1 + @str1
set @count=@count+1
END
print len(@str1)
print @count
Results :-
1073741824
30
So in conclusion, I could say nvarchar(max) can contain till 1073741824 many characters. I haven't tried more than this. Lots of reference in Internet also says that it can contain 2GB of data and a character is 2 bytes each, which adds up to that number.
