If you want Excel VBA to perform a task that returns a result you can use a function. Place a function into a module (In the Visual Basic Editor click Insert Module). For example the function with name Area.

Function Area(x As Double y As Double) As Double

Area = x * y

End Function

Explanation: This function has two arguments (of type Double) and a return type (the part after As also of type Double). You can use the name of the function (Area) in your code to indicate which result you want to return (here x * y).

You can now refer to this function (in other words call the function) from somewhere else in your code by simply using the name of the function and giving a value for each argument.

Place a command button on your worksheet and add the following code lines:

Dim z As Double

z = Area(3 5) + 2

MsgBox z

Explanation: The function returns a value so you have to ‘catch’ this value in your code. You can use another variable (z) for this. Next you can add another value to this variable (if you want). Finally display the value using a MsgBox.

Result when you click the command button on the sheet:

If you want Excel VBA to perform some actions you can use a sub. Place a sub into a module (In the Visual Basic Editor click Insert Module). For example the sub with name Area.

Sub Area(x As Double y As Double)

MsgBox x * y

End Sub

Explanation: This sub has two arguments (of type Double). It does not have a return type! You can refer to this sub (call the sub) from somewhere else in your code by simply using the name of the sub and giving a value for each argument.

Place a command button on your worksheet and add the following code line:

Area 3 5

Result when you click the command button on the sheet:

Can you see the difference between the function and the sub? The function returned the value 15. We added the value 2 to this result and displayed the final result. When we called the sub we had no more control over the result (15) because a sub cannot return a value!