Question

sp_helpdb returns strings like ‘50000.255 MB’ in the db_size column.

These strings are culture-dependent; the above string will mean 2 different things in US and Germany (in the latter, the dot char is used as a group separator, similar to the comma in US).

Is there another method which returns a numeric value, culture-independent?

Answer 1

 Use YourDB;
 SELECT SUM(Size / 128.0) As FileSize from sys.database_files;

This returns the size in MB as a numeric, you should be able to do what you like with it from there.

Note: size returns the number of 8KB pages in a given database file.

http://msdn.microsoft.com/en-us/library/ms174397.aspx