The DAYS360 function with example in Excel

The DAYS360 function in Excel calculates the number of days between two dates based on a 360-day year, where each month is assumed to have 30 days. This function is commonly used in accounting calculations. Let’s break down how it works and explore some examples:

1. Syntax:

   =DAYS360(start_date, end_date, [method])
   

   • start_date: The initial date.
   • end_date: The final date.
   • [method]: An optional argument that specifies the calculation method (U.S. or European).

2. Purpose: The DAYS360 function helps compute payments when accounting systems use a 360-day year (twelve 30-day months).

3. Methods:

   • U.S. (NASD) method (default):
     • If the starting date is the last day of a month, it becomes equal to the 30th day of the same month.
     • If the ending date is the last day of a month and the starting date is earlier than the 30th day of that month, the ending date becomes equal to the 1st day of the next month; otherwise, the ending date becomes equal to the 30th day of the same month.
   • European method:
     • Starting dates and ending dates that occur on the 31st day of a month become equal to the 30th day of the same month.

4. Examples: Let’s consider the following data:

   Table

   Dates	Description
   1-Jan-11	Start date
   30-Jan-11	Intermediate date
   1-Feb-11	Intermediate date
   31-Dec-11	End date

   • To find the number of days between 1/30/2011 and 2/1/2011 (based on a 360-day year):

     =DAYS360(A3, A4)
     

     Result: 1

   • To calculate the days between 1/1/2011 and 12/31/2011 (based on a 360-day year):

     =DAYS360(A2, A5)
     

     Result: 360

   • Days between 1/1/2011 and 2/1/2011 (based on a 360-day year):

     =DAYS360(A2, A4)
     

     Result: 30

Remember to replace cell references (A2, A3, A4, A5) with your actual date cells. The DAYS360 function is handy for financial calculations where a 360-day year is assumed.