Writing comments in Excel Visual Basic

Written by Andy Brown

In this tutorial

Writing Comments
Changing the Colour of Comments
Displaying the Correct Toolbar
Commenting Out (and Back In)

All good programmers use comments liberally. To see why, consider the following excerpt of code, taken from Excel VBA:

Range("A1").Select

ActiveCell.End(xlDown).Select

ActiveCell.Offset(1, 0).Select

ActiveCell.Value = InputBox("Choose a Wise Owl")

Now compare this with exactly the same code, but commented:

'go to the bottom of column A

Range("A1").Select

ActiveCell.End(xlDown).Select

'go one cell further, to first blank cell …

ActiveCell.Offset(1, 0).Select

'… and set the value of this cell to be the Wise Owl name typed in

ActiveCell.Value = InputBox("Choose a Wise Owl")

We think the second code excerpt is far easier to read and understand!

Here are 2 good reasons to use comments in your code:

Reason	Notes
Intelligibility	You may understand your code now, but will you know what it was meant to do when you revisit it in 6 months' time? Will your colleague understand it when you leave your company? Comments make code easier to read and follow.
Clearer thought process	It sounds strange to say it, but commenting code as you write will help you think about what you're trying to do. If you write the line: 'go to the bottom cell in the first column you've already thought about what you're trying to achieve, and are more likely to translate this into code correctly.

As a rough guide, you should add a comment for every 2-3 lines of code on average.

That's why you should comment your VBA code - now read on for how to do it!

This online training blog shows how to add comments to VBA (Visual Basic for Applications) code. The ideas shown work in Access, Word, PowerPoint and all other MS Office applications, but the diagrams come from Excel Visual Basic.

An example of commented code in Visual Basic for Excel

Writing Comments

Any comment in VBA begins with a single apostrophe character ('). When you type in a comment and press the Enter key, the line will go green. For comments spanning multiple lines, you'll need to type the ' key multiple times: