Calculates the number of days between two dates based on a 360-day year (twelve 30-day months), which is used in some accounting calculations. Use this function to help compute payments if your accounting system is based on twelve 30-day months.

DAYS360(start_date,end_date,[method])

• Start_date, end_date (required):
  The two dates between which you want to know the number of days.
  If start_date occurs after end_date, the DAYS360 function returns a negative number.
• Method (optional):
  A logical value that specifies whether to use the U.S. or European method in the calculation
• Method set to false or omitted:
  the DAYS360 function uses the U.S. (NASD) method. If the starting date is the 31st of a month, it becomes equal to the 30th of the same month. If the ending date is the 31st of a month and the starting date is earlier than the 30th of a month, the ending date becomes equal to the 1st of the next month, otherwise the ending date becomes equal to the 30th of the same month. The month February and leap years are handled in the following way:
  On a non-leap year the function =DAYS360("2/28/93", "3/1/93", FALSE) returns 1 day because the DAYS360 function ignores the extra days added to February.
  On a leap year the function =DAYS360("2/29/96","3/1/96", FALSE) returns 1 day for the same reason.
• Method Set to true:
  When you set the method parameter to TRUE, the DAYS360 function uses the European method. Starting dates or ending dates that occur on the 31st of a month become equal to the 30th of the same month. The month February and leap years are handled in the following way:
  On a non-leap year the function =DAYS360("2/28/93", "3/1/93", TRUE) returns 3 days because the DAYS360 function is counting the extra days added to February to give February 30 days.
  On a leap year the function =DAYS360("2/29/96", "3/1/96", TRUE) returns 2 days for the same reason.