WorksheetFunction.Log10 (Excel)

Returns the base-10 logarithm of a number.

Log10 (Arg1)

Arg1: Number - the positive real number for which you want the base-10 logarithm.

Dim dblArg1 As Double: dblArg1 = 
Dim dblLog10 As Double
dblLog10 = WorksheetFunction.Log10(Arg1:=dblArg1)