Please Note: This article is written for users of the following Microsoft Excel versions: 2007, 2010, 2013, 2016, 2019, and Excel in Office 365. If you are using an earlier version (Excel 2003 or earlier), this tip may not work for you. For a version of this tip written specifically for earlier versions of Excel, click here: Understanding Functions in Macros.

Understanding Functions in Macros

by Allen Wyatt
(last updated April 24, 2020)

6

You already know that you can use subroutines in your macros. VBA also allows you to define functions that can be used in your macros. The difference between functions and subroutines is that functions can return values, whereas subroutines cannot. Consider the following macro:

Sub Macro1()
    TooMany = TestFunc
    If TooMany Then MsgBox "Too many columns selected"
End Sub
Function TestFunc()
    TestFunc = False
    If Selection.Columns.Count > 10 Then
       TestFunc = True
    End If
End Function

The macro (Macro1) calls the TestFunc function. This function returns either the value False or True, depending on a test it performs. Macro1 then acts upon the value returned. Notice that the function name can appear on the right side of an equal sign. This makes functions very powerful and an important part of any program. Within the function the result is assigned to TestFunc, which is the name of the function itself; this is the value returned by the function.

As with subroutines, you can also pass parameters to your functions. This is illustrated in the following macro:

Sub Macro1()
    A = 12.3456
    MsgBox A & vbCrLf & RoundIt(A)
End Sub
Function RoundIt(X) As Integer
    RoundIt = Int(X + 0.5)
End Function

This simple macro (Macro1) defines a number, and then uses a message box to display it and the result of passing the number to the RoundIt function. The output is 12.3456 and 12. Notice that the parameter should be passed to the function within parentheses. Also notice that the function does not use the same variable name as it was passed. This is because VBA reassigns the value of X (what the function needs) so it matches the value of A (what the program is passing to the function). The important thing to remember in passing parameters to functions is that your program must pass the same number of parameters as the function expects and the parameters must be of matching types and in the proper order.

Note:

If you would like to know how to use the macros described on this page (or on any other page on the ExcelTips sites), I've prepared a special page that includes helpful information. Click here to open that special page in a new browser tab.

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (11765) applies to Microsoft Excel 2007, 2010, 2013, 2016, 2019, and Excel in Office 365. You can find a version of this tip for the older menu interface of Excel here: Understanding Functions in Macros.

Author Bio

Allen Wyatt

With more than 50 non-fiction books and numerous magazine articles to his credit, Allen Wyatt is an internationally recognized author. He is president of Sharon Parq Associates, a computer and publishing services company. ...

MORE FROM ALLEN

Counting Words the Old Fashioned Way

One way to specify word count is to count characters and divide by five. If you still need this old-fashioned way of ...

Discover More

Make that Chart Quickly!

Need to generate a chart in the fastest possible way? Just use this shortcut key and you'll have one faster than you can ...

Discover More

Renaming and Deleting Icons

Want to change the name of a desktop icon or get rid of it entirely? It's easier to do than you probably think!

Discover More

Solve Real Business Problems Master business modeling and analysis techniques with Excel and transform data into bottom-line results. This hands-on, scenario-focused guide shows you how to use the latest Excel tools to integrate data from multiple tables. Check out Microsoft Excel 2013 Data Analysis and Business Modeling today!

More ExcelTips (ribbon)

Triggering an Event when a Worksheet is Deactivated

One way you can use macros in a workbook is to have them automatically triggered when certain events take place. Here's ...

Discover More

Running a Procedure when a Workbook is Opened

Ever want to have Excel run a procedure whenever you open a workbook? It's not as difficult as you might think. Here's how.

Discover More

Buttons Don't Stay Put

Excel allows you to easily add all sorts of objects and controls to your workbook. Sometimes, though, those items might ...

Discover More
Subscribe

FREE SERVICE: Get tips like this every week in ExcelTips, a free productivity newsletter. Enter your address and click "Subscribe."

View most recent newsletter.

Comments

If you would like to add an image to your comment (not an avatar, but an image to help in making the point of your comment), include the characters [{fig}] in your comment text. You’ll be prompted to upload your image when you submit the comment. Maximum image size is 6Mpixels. Images larger than 600px wide or 1000px tall will be reduced. Up to three images may be included in a comment. All images are subject to review. Commenting privileges may be curtailed if inappropriate images are posted.

What is six minus 3?

2020-04-24 09:51:49

Kevin Moynihan

I often write code using the 4 or 5 line approach as opposed to the one line.
And the reason is that often the code is inside a repetitive loop, where the operation will be evaluated dozens or hundreds
of times. So good programming says I should reset the variables each time I go through to evaluate the expression.
However, if the expression is inside a function, and the function is in a loop, then you could write the function suing the simplest form possible


2020-02-08 15:55:11

John Mann

R Grealish. I'm very much a novice at VBA (If I've even reached novice level). In your last example, I'm inclined to wonder what would be the value of "reult" if the logical test fails, and result has not been set to false before hand?


2015-12-08 10:21:47

R Grealish

I think the point of my comment has been misunderstood (My fault in not expressing my self well).

I was not commenting on the specific tip whose purpose I fully understand. I took the code in the function as an example of a more general point I was trying to make which was why use more code than you need to. I will construct an example without using the code in the tip.

Consider the following VBA code fragment (which is not necessarily part of any function or subroutine)

result = false
if a > b then
result = true
end-if

In my view this code fragment could be written more succinctly as

result = a > b


2015-12-07 13:00:27

R Lowe

R Grealish, in fact a function call isn't necessary. The function call could have been replaced with:

If Selection.Columns.Count > 10
Then MsgBox "Too many columns selected"
End If

The point of this tip is just to demonstrate the difference between subroutines and functions.


2015-12-07 12:55:53

CJ

The example for TextFunc should work, but best programming practices suggest that the TextFunc function be defined as returning a Boolean data type.


2015-12-05 07:19:59

R Grealish

In many code examples, code of the following structure appears

TestFunc = False
If Selection.Columns.Count > 10 Then
TestFunc = True
End If

(taken from the tip).

It is unclear to me why the simpler and equivalent code is not used

TestFunc = Selection.Columns.Count > 10


This Site

Got a version of Excel that uses the ribbon interface (Excel 2007 or later)? This site is for you! If you use an earlier version of Excel, visit our ExcelTips site focusing on the menu interface.

Newest Tips
Subscribe

FREE SERVICE: Get tips like this every week in ExcelTips, a free productivity newsletter. Enter your address and click "Subscribe."

(Your e-mail address is not shared with anyone, ever.)

View the most recent newsletter.