The Excel DAYS360 function returns the number of days between two date serial numbers based on a 360-day year, or twelve 30-day months. This method is used in some accounting calculations.
Excel DAYS360 Function Syntax
Syntax: | =DAYS360(start_date, end_date, [method]) |
start_date | A date in a format Excel recognises known as the date-time serial number, or text |
end_date | A date in a format Excel recognises known as the date-time serial number, or text |
[method] | Optional logical value TRUE/FALSE – see more below. |
The optional 'method' argument is a logical value (TRUE/FALSE) that specifies whether to use the U.S. or European method. If omitted it is treated as FALSE.
FALSE: U.S. (NASD) method. 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 a 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.
TRUE: 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.
Excel DAYS360 Function Examples

Notice the difference between the TRUE/FALSE method results.
Tip: DAYS360 works with dates stored as text (cells B27 & B35), but this is not reliable. It's always best to work with date serial numbers.
Note: Only the date portion of a date-time serial number is used by DAYS360. Any time element is ignored. As a result, only whole days are returned.
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