Date Filtered Calculation For Monthly to Weekly Targets

Hi Everyone,

I've struggled with a solution for a problem, I have tried using running totals but not all employees add data for each day so the calculations have been off.

TARGETS:

Employee A - January - 20 hours

Employee A - February - 18 hours

Employee B - January 24 hours

etc.

ACTUALS:

Daily entry for each day worked, e.g. January 1 - 2 hours, January 3 - 4 hours.

Is there a way I can sum the hours worked over that month (I have this working fine), and then use some formula to calculate the target based on a date filter. So if the first 2 weeks of January are selected, it'll take 14th day out of 31 multiplied by target to give how many hours should have been worked. And if the whole month is selected, it will take the full 31/31*target?

Then a measure for the difference between the two numbers for a "Delta"?

Appreciate any advice,

George