DAYS360
Returns the difference between two dates based on the 360 day year used in interest calculations.
This function is part of the Open Document Format for Office Applications (OpenDocument) standard Version 1.2. (ISO/IEC 26300:2-2015)
DAYS360(Date1; Date2[; Type])
If Date2 is earlier than Date1, the function will return a negative number.
The optional argument Type determines the type of difference calculation. If Type = 0 or if the argument is missing, the US method (NASD, National Association of Securities Dealers) is used. If Type <> 0, the European method is used.
When entering dates as part of formulas, slashes or dashes used as date separators are interpreted as arithmetic operators. Therefore, dates entered in this format are not recognized as dates and result in erroneous calculations. To keep dates from being interpreted as parts of formulas use the DATE function, for example, DATE(1954;7;20), or place the date in quotation marks and use the ISO 8601 notation, for example, "1954-07-20". Avoid using locale dependent date formats such as "07/20/54", the calculation may produce errors if the document is loaded under different locale settings.
Unambiguous conversion is possible for ISO 8601 dates and times in their extended formats with separators. If a #VALUE! error occurs, then unselect Generate #VALUE! error in Collabora Office - PreferencesTools - Options - Collabora Office Calc - Formula, button Details... in section "Detailed Calculation Settings", Conversion from text to number list box.
=DAYS360("2000-01-01";NOW()) returns the number of interest days from January 1, 2000 until today.