Woking from evocandy's answer I came up with this basic code.
time1 = Timer
Range("A1").Calculate ' Or the cell containing the Formula I want. OR use Sheets("Sheet1").Calculate for the calculation including concated columns
time2 = Timer
CalculationTime = Time2-Time1
In order for this to work i had to Isolate sample data to new empty worksheets and disable the Automatic Refresh in Excel as to make sure it doesn't time any other Calculations.