# Why 730 hours per month is often used in monthly calculations? Every month will have a different number of hours, mostly 720 for 30 days-month and 744 for 31 days-month. February and leap years makes it even more complicated. So to keep is simple, AWS, and lots of other people, assume that a year has 365 days and each day is 24 hours which means that a year has 8760 hours. 24\*365 To get an average number of hours per month divide 8760 by 12 and you get 730. So 730 is the average numbers of hours per month for a standard year (365 days) . in summary: 24\*365/12=730 [[Interesting numbers related to time]]