Excel Function Now and automatic Updating

[campbemr]

In one section of my spreadsheet I want to calculate the elapsed time. So I have a formula like
=Now() - $B$12
where $B$12 has the start date

I do not know if Now() would be the correct function in this instance or not. Because the way that it is working it will calculate whenever the cell B12 is changed and I don't want that. I want the cell to change with every minute elapsed. Is there some way that this cell can be formatted to do this or do I have to write a macro. And if so what event may I have to use.

 

[acron]

You could use the OnTime VBA method, as follows

Sub UpdateTimer()
    [Duration] = Now() - [StartTime]
    Application.OnTime Now + _
        TimeValue("0:01:00"), "UpdateTimer"
End Sub

where StartTime is the cell that holds the start date/time and duration is the cell you wish to update every minute.

The procedure schedules itself to update every minute.

A.C.