Excel: I need a formula that will count months between two dates. If it's 1-15 it should be a half month. Any ideas?
Assuming the dates are in G8, H8
=DATEDIF(G8, H8, "m") +1 -IF(DAY(G8) <16,0, 0.5)
If someone want's a more precise solution for month fractions, they could use
=(date1 - date2)/(365/12)
It considers a month to be on average 365/12 days long,
I can use it for simple (approximate) monthly interest calculations like this one:
$1000 charged 1.5% per month from the day of this posting until the current date
=1000*(1.015)^( (TODAY()-DATE(2018,2,6))/(365/12) )