DateDiff Function

DateDiff Function returns the number of time intervals between two dates.

Syntax

DateDiff(interval,date1,date2[,firstdayofweek[,firstweekofyear]])

Parameter	Description
interval	Required. The unit of time used to calculate the difference between date1 and date2. Can be one of the following values: * yyyy - Year * q - Quarter * m - Month * y - Day of year * d - Day * w - Weekday * ww - Week of year * h - Hour * n - Minute * s - Second
date1,date2	Required. Date expressions. The two dates to be used in the calculation.
firstdayofweek	Optional. Specifies the first day of the week. If not specified, vbSunday is assumed. Can be one of the following values: * 0 = vbUseSystemDayOfWeek - Use NLS API setting * 1 = vbSunday - Sunday (default) * 2 = vbMonday - Monday * 3 = vbTuesday - Tuesday * 4 = vbWednesday - Wednesday * 5 = vbThursday - Thursday * 6 = vbFriday - Friday * 7 = vbSaturday - Saturday
firstweekofyear	Optional. Specifies the first week of the year. If not specified, vbFirstJan1 is assumed. Can be one of the following values: * 0 = vbUseSystem - Use NLS API setting * 1 = vbFirstJan1 - Week in which January 1 occurs (default) * 2 = vbFirstFourDays - Week that has at least four days in the new year * 3 = vbFirstFullWeek - First full week of the year

Examples

Example 1

Difference between January 31, 2009 and January 31, 2010:

fromDate="31-Jan-09 00:00:00" toDate="31-Jan-10 23:59:00" document.write(DateDiff("yyyy",fromDate,toDate) & "
") document.write(DateDiff("q",fromDate,toDate) & "
") document.write(DateDiff("m",fromDate,toDate) & "
") document.write(DateDiff("y",fromDate,toDate) & "
") document.write(DateDiff("d",fromDate,toDate) & "
") document.write(DateDiff("w",fromDate,toDate) & "
") document.write(DateDiff("ww",fromDate,toDate) & "
") document.write(DateDiff("h",fromDate,toDate) & "
") document.write(DateDiff("n",fromDate,toDate) & "
") document.write(DateDiff("s",fromDate,toDate) & "
")

The above example outputs:

1
4
12
365
365
52
53
8783
527039
31622340

[Try it yourself »]

Example 2

How many weeks between December 31, 2009 and December 31, 2012 (starting on Monday):

fromDate=CDate("2009/12/31") toDate=CDate("2012/12/31") document.write(DateDiff("w",fromDate,toDate,vbMonday))