this source:
Date1: 2008-04-01
Date2: 2008-03-01
{(sub (udays {$:Date1}) (udays {$:Date2}) )}
{(div (sub (ftime %s {$:Date1}) (ftime %s {$:Date2})) 86400)}
produces this output:
Date1: Tuesday, 1 April 2008
Date2: Saturday, 1 March 2008
30
30.958333333333
~Hans