changing the value in F20 of sheet 3, either by editing the cell or by code,
will fire the macro if you place it in the sheet module of sheet3

right click on the sheet tab and select view code, then put it in that
module.

see Chip Pearson's site on events

http://www.cpearson.com/excel/events.htm

--
Regards,
Tom Ogilvy

"myleslawrence" wrote in message
...
Thanks Tim.
What calls the Worksheet_Change subroutine? If in your example, F20
triggers the change, how do I get that to happen and call the sub?

"Tom Ogilvy" wrote in message
...
In Sheet1!F5 put in a formula like

=Sheet2!F20

This would update whenever a calculation occured.

Otherwise you would have to use a worksheet_change event in sheet 3.

What cell in Sheet3 would trigger the change

Assume F20 in Sheet3

Private Sub Worksheet_Change(ByVal Target As Range)
if Target.Address = "$F$20" then
worksheets("Sheet1").Range("F5").Value = _
Worksheets("Sheet2").Range("F20").Value
End If
End Sub

--
Regards,
Tom Ogilvy

"myleslawrence" wrote in message
...
I'm trying to figure out how to update the value on sheet1 in column F,
row
5 with the value on sheet2 column F, row 20 whenever that value on
sheet3
changes. If someone would give a tip I'd appreciate it.