I have a sheet that will list each day of the month as well as totals for
several categories for each day. I also have an end-month goal. I want to
show what each number should be at for any given day, but I want to make sure
that it's accurate (ie, whether the month has 28, 30 or 31 days).

For example, let's say a target goal is $3,000. Over 30 days that would be
$100 per day. But for a month with more or less than 30 days, I want the
formula to remain accurate without having to redo the formula every month.
Basically what I want to do is divide the goal by the days in the month, then
give a running rate to match against their actual performance.