Calculate minutes between two dates

Simple question but always a pain in the ass in finding the right solution:

select 
round(
(to_date('12.08.2014 12:30','dd.mm.yyyy hh24:mi')
-to_date('12.08.2014 11:30','dd.mm.yyyy hh24:mi')
) * 24 * 60
,0) as result_in_minutes
from dual;