You need to call the Sub procedure "Timer", this is usually done by calling it within another Sub/Function if you want the countdown to begin after you enter a value into cell "A1" and stop when you enter data into another range, then you need to listen for a change to those cells and create a boolean for the Timer sub procedure, so it knows when to stop, to do this create a "Worksheet_Change" sub procedure, this will listen to the worksheet for any changes, we then create a whitelist of ranges that will run our code.


Sub Worksheet_Change(ByVal Target As Range)

'Boolean default value
Dim TimerActive As Boolean: TimerActive = True

'This is where we call the Timer and get our value set in G2
If Not Intersect(Target, Range("A1")) Is Nothing Then

If IsEmpty(Target) Then TimerActive = False: Exit Sub

On Error GoTo Errr:

Dim i As Integer: i = Target

Me.Range("G2").Value = i

Call Timer

ElseIf Not Intersect(Target, Range("B2:C57")) Is Nothing Then

TimerActive = False

If IsEmpty(Target) Then Exit Sub

'Add more code here if needed

End If

'Error processing
Exit Sub
Errr:
MsgBox "A1 Must be integer"

End Sub

I also included the ability to delete the value in A1, which will also stop the countdown, now, in the "Timer" sub procedure, at the beginning create an if statement to check whether or not our boolean "TimerActive" equals False, if it does then we need to Exit Sub. To change the Timers colour when counting down, you need to edit the "ResetTimer" sub procedure, and add an if statement, similar to the one that already exists, "If xRng <= 30", within that statement we add the colour we want to use "xRng.Font.Color = vbRed" you can also change the colour using "xRng.Font.Color = RGB(0,0,0)", do the same in the "Timer" procedure to reset the colour, do this before the boolean if statement, so that the colour always reverts back to its default, even when manually stopped.

Hello Jose, I noticed the author did not respond to your comment, I've just recently discovered his post and thought I'd help you if you still need it. To trigger the timer, you need to call the sub procedure, so let us assume you have a sub in your worksheet that checks for any changes to cell A1, example:


########
Sub Worksheet_Change(ByVal Target As Range)


Dim rInt As Range: Set rInt = Intersect(Target, Range("A1"))


If Not rInt Is Nothing Then


On Error GoTo Err:
Dim i As Integer: i = Me.Range("A1").Value


If not IsEmpty(vCell) Then
Call Timer <<< This is where you call the timer
End If


End If
Exit Sub
Err:
MsgBox "Integer Only"
End Sub
########


The "Timer" Sub procedure is used to set the event, we basically want this to run every 1 second in the future which is why we use now + TimeValue("00:00:01"), if you wanted to update the timer in your cell every two seconds or every minute, you adjust the TimeValue accordingly.


The "ResetTime" sub procedure is where we do all the heavy lifting, in this sub procedure, if you want to change the colour of the timer to red, once it reaches 30 seconds, you can do this by adding a simple if statement, just like the one that already exists within the procedure.


If xRng.Value <= 30 Then
xRng.Font.Color = vbRed
End If