VBA DateDiff Function

DateDiff Description

Returns the difference between two date values, based on the interval specified.

Simple DateDiff Examples

Here is a simple DateDiff example:

Sub DateDiff_Year()
    MsgBox DateDiff("yyyy", #1/1/2019#, #8/1/2021#)
End Sub

This code will return 2. This is difference on year (indicated by “yyyy”) between 2 days. (2021 – 2019 = 2)

In the example above, changing the positions of date1 and date2.

Sub DateDiff_Year()
    MsgBox DateDiff("yyyy", #8/1/2021#, #1/1/2019#)
End Sub

This code will return -2.

DateDiff Syntax

In the VBA Editor, you can type  “DateDiff(” to see the syntax for the DateDiff Function:

The DateDiff function contains 5 arguments:

Interval: Time unit (Days, Months, Years, etc.). Enter as string. (ex. “m” for Month)

Setting	Description
yyyy	Year
q	Quarter
m	Month
y	Day of Year
d	Day
w	Weekday
ww	Week
h	Hour
n	Minute
s	Second

Date1, Date2: Two dates you want to use in the calculation.

FirstDayOfWeek: A constant that specifies the first day of the week. This is optional. If not specified, Sunday is assumed.

Constant	Value	Description
vbUseSystem	0	Use the NLS API setting.
vbSunday	1	Sunday (default)
vbMonday	2	Monday
vbTuesday	3	Tuesday
vbWednesday	4	Wednesday
vbThursday	5	Thursday
vbFriday	6	Friday
vbSaturday	7	Saturday

FirstWeekOfYear: A constant that specifies the first week of the year. This is optional. If not specified, the first week is assumed to be the week in which January 1 occurs.

Constant	Value	Description
vbUseSystem	0	Use the NLS API setting.
vbFirstJan1	1	Start with week in which January 1 occurs (default).
vbFirstFourDays	2	Start with the first week that has at least four days in the new year.
vbFirstFullWeek	3	Start with first full week of the year.

 

Examples of Excel VBA DateDiff Function

Referencing Dates

To start, we will demonstrate different ways to reference dates using the VBA DateDiff Function.

Each of these DateDiff functions produce the same result:

Sub DateDiff_ReferenceDates()

    MsgBox DateDiff("m", #4/1/2019#, #8/1/2021#)

    MsgBox DateDiff("m", DateSerial(2019, 4, 1), DateSerial(2021, 8, 1))

    MsgBox DateDiff("m", DateValue("April 1, 2019"), DateValue("August 1, 2021"))

End Sub

Or you can reference cells containing dates:

Sub DateDiff_ReferenceDates_Cell()

    MsgBox DateDiff("m", Range("C2").Value, Range("C3").Value)
    
End Sub

Or create and reference date variables:

Sub DateDiff_Variable()

    Dim dt1 As Date, dt2 As Date
    dt1 = #4/1/2019#
    dt2 = #8/1/2021#

    MsgBox DateDiff("m", dt1, dt2)

End Sub

Using Different Units of Interval

Quarters

Sub DateDiff_Quarter()
    MsgBox "the number of quarters: " & DateDiff("q", #1/1/2019#, #1/1/2021#)
End Sub

Months

Sub DateDiff_Month()
    MsgBox "the number of months: " & DateDiff("m", #1/1/2019#, #1/1/2021#)
End Sub

Days

Sub DateDiff_Day()
    MsgBox "the number of days: " & DateDiff("d", #1/1/2019#, #1/1/2021#)
End Sub

Weeks

Sub DateDiff_Week()
    MsgBox "the number of weeks: " & DateDiff("w", #1/1/2019#, #1/1/2021#)
End Sub

Hours

Sub DateDiff_Hour()
    Dim dt1 As Date
    Dim dt2 As Date
    Dim nDiff As Long
    
    dt1 = #8/14/2019 9:30:00 AM#
    dt2 = #8/14/2019 1:00:00 PM#
    
    nDiff = DateDiff("h", dt1, dt2)

    MsgBox "hours: " & nDiff
End Sub

Minutes

Sub DateDiff_Minute()
    MsgBox "mins: " & DateDiff("n", #8/14/2019 9:30:00 AM#, #8/14/2019 9:35:00 AM#)
End Sub

Seconds

Sub DateDiff_Second()
    MsgBox "secs: " & DateDiff("s", #8/14/2019 9:30:10 AM#, #8/14/2019 9:30:22 AM#)
End Sub