The Excel DAYS360 Function

Related Functions:
DAYS
NETWORKDAYS

Basic Description

The Excel Days360 function returns the number of days between 2 dates, based on a 360-day year (12 x 30 months).

The format of the function is:

DAYS360( start_date, end_date, [method] )

where the arguments are as follows:

start_date-The start of the period
end_date-The end of the period
[method]-

An optional logical argument, which gives the method to be used in the calculation. This can be either:

FALSE (or omitted)-US (NASD) method used
TRUE-European method used

US vs. European Method

US Method:

  • If start date is last day of month it is set to 30th of that month;
  • If end date is last day of month, then:
  • If start date is last day of month the end date is set to the 1st of the following month;
  • Otherwise, the end date is set to 30th of that month.

European Method:

  • If start date is last day of month it is set to 30th of that month;
  • If end date is last day of month, then it is set to 30th of that month.
The financial day count basis rules are explained in detail on the Wikipedia Day Count Convention page

Date Arguments

Note that date arguments that are supplied to Excel functions as text representations of dates can be interpreted differently, depending on the date systems and date interpretation settings on your computer.

Therefore the start_date and end_date arguments should be input to the Days360 function as either:

or

Excel Days360 Function Examples

The spreadsheets below show simple examples of the Excel Days360 function.

 Formulas:
 AB
101-Jan-2015=DAYS360( A1, A2 )
231-Jan-2015=DAYS360( A1, A2, TRUE )
301-Feb-2015=DAYS360( A1, A3, FALSE )
4 =DAYS360( A3, DATE( 2015, 2, 2 ) )
 Results:
 AB
101-Jan-201530
231-Jan-201529
301-Feb-201530
4 1

In the above example:

Note also that, as recommended by Microsoft, in all four calls to the Days360 function, the start_date and end_date arguments have been supplied as either cell references or as values returned from functions (in cell B4, the Date function is used to supply the end_date argument).


Further information and examples of the Excel DAYS360 function can be found on the Microsoft Office website.


DAYS360 Function Errors

Error
#NUM!-Occurs if either of the supplied start_date or end_date arguments are numeric values, but are not recognised as valid dates.
#VALUE!-

Occurs if either:

  • Either of the supplied start_date or end_date arguments are text values that can not be interpreted as dates.
  • The supplied [method] argument is non-numeric.