Overview
When workbooks get slow, you need to know exactly how long calculations take. These two macros provide precise timing: Calculation_Timer measures a single cell's recalculation time, while Calculation_Timer_Full times a complete workbook rebuild.
Calculation_Timer works by re-entering the active cell's formula and triggering a calculate, measuring the elapsed time with VBA's Timer function to four decimal places. Calculation_Timer_Full calls CalculateFullRebuild, which forces Excel to discard all cached results and recompute everything from scratch.
When To Use Each
- Calculation_Timer: Use to benchmark a specific complex formula. Re-enters the formula and calculates, giving you the isolated cost of that one cell
- Calculation_Timer_Full: Use to measure total workbook performance. CalculateFullRebuild is the most thorough recalculation mode, clearing all caches and dependency trees
The VBA Code
Public Sub Calculation_Timer()
Dim StartTime As Double: StartTime = Timer
' Recalculate just the active cell's formula
Dim Frm As String: Frm = ActiveCell.Formula2
ActiveCell.Formula2 = Frm
Application.Calculate
Dim EndTime As Double: EndTime = Timer
MsgBox Round(EndTime - StartTime, 4) & " seconds"
End Sub
Public Sub Calculation_Timer_Full()
Dim StartTime As Double: StartTime = Timer
' Full workbook recalculation rebuild
Application.CalculateFullRebuild
Dim EndTime As Double: EndTime = Timer
MsgBox Round(EndTime - StartTime, 4) & " seconds"
End Sub
Final Thoughts
These timers are the starting point for any Excel performance optimization. By measuring before and after changes, you can quantify the impact of formula refactoring, helper column additions, or structural changes to your workbook.