[Originally posted June 2012. Last updated in June 2021. For a video on this topic, click: https://youtu.be/otPTkvnrPlc.]
The Mail Merge feature of Microsoft Word is one of my favorite parts of the program. It is extremely powerful for creating labels and customized letters, emails, or reports. Once you learn how to use it, you can save countless hours of work. Unfortunately, the task of learning to master all of its idiosyncrasies can give you countless headaches.
One of the perennial annoyances of Mail Merge is its inability to format numbers from an Excel spreadsheet correctly. For example, a sales result in Excel appears as 100 but in Word it suddenly becomes 99.99999999996!
Fortunately, there are no less than three different ways to get Mail Merge numbers to appear the way they should.
[Note for users of various versions of Microsoft Office: The steps presented here are for Office 2016 as of August 2018, but the steps needed for older and newer versions of Word and Excel are very similar if not identical.]
1. Modify the Excel Spreadsheet
The first way is to avoid the problem: In the Excel worksheet, insert a column with a formula that converts the Excel numbers or dates into a text format that is exactly the same as what you would want to appear in your Mail Merge document.
To do this, you need to use Excel’s TEXT function, which enables you to convert a number or date into its equivalent text formatted exactly the way you desire. The downside is that you need to know certain formatting codes. Although these codes are identical to those used in the Custom Number formatting feature of Excel, they are rarely seen by most Excel users.
For example, the formulas TEXT(B3, “$#,##0.00”) and TEXT(C5, “M/dd/yy”) convert number and date data into textual data (in this case, “$12,345.67” and “12/01/10”).
(Tip: It is a good idea to format the cells containing these formulas in a different style, say, italic, or some unusual color to remind you that these numbers are simply text. In older versions of Excel, these “numbers” could not be used in calculations. In Excel 2016, they can be used in all formulas except aggregate functions, such as, SUM and AVERAGE.)
The advantage of formatting numbers and dates as text is that text is transported from Excel into a Word Mail Merge document unmolested. Well, almost unmolested. Formatting options such as font, size, and color do not make the trip.
Format Codes for Excel’s TEXT Function
A collection of the most commonly used codes is presented at the right. A key thing to remember is that both “0” and “#” act as placeholders for digits, but “0” will force leading or trailing zeros to appear. The “#” placeholder will be replaced by a digit only if it is not a leading or trailing zero. Thus, the code “00000” will ensure that the leading zero is not truncated from New Jersey postal zip codes.
These codes for numbers, dates, and times can be used in the TEXT function or in Excel’s Custom number formats. As an extra bonus, they can also be used in the “Numeric Switches” in Word Mail-Merge Fields described in the next section.
Unfortunately, there is a slight difference between the way these codes work in Excel and Word in Microsoft Office 2013. In Excel, you can use either “M” or “m” for months or minutes. In almost all cases, Excel is smart enough to figure out which units you are talking about. But Word is not so smart, and you must use the capitalized letter to refer to months. Also, Excel has an additional code, “MMMMM”, which returns a single letter abbreviation for the month (e.g., “J, F, M, A, …”).
Supplementing a spreadsheet table with a few columns featuring TEXT functions is a simple and direct approach. Just remember that these cells may look like they contain numbers, but they cannot be used in SUM or AVERAGE functions. If you need to convert them into numbers again, just use the VALUE function.
Handle with Care: The ROUND Function
Instead of the TEXT() function, some users prefer to use the ROUND() function to trim off extra decimal places. As its name implies, Excel’s ROUND() function will permanently round a number up or down to the number of decimal places you specify. The advantage is that the rounded number is not text and can still be used for further calculations. In many cases, the ROUND() function will work well with Mail Merge, but you may want to steer clear of it because of the following reasons:
- The ROUND function will not preserve the dollar sign or the thousands separator (comma)
- The ROUND function will truncate trailing zeros
- The ROUND function sometimes causes Mail Merge to display the wrong number of decimal places. For example, a Mail Merge document occasionally shows 4 decimal places when the ROUND function had specified 2 or 3.
In rare cases, the ROUND function causes Mail Merge to show a slightly different number. For example, instead of displaying 1.0014, Mail Merge showed 1.0013.
Okay. But let’s say that you can’t or don’t want to change your Excel spreadsheet. Well, there is something we can do in Word:
2. Use a “Numeric Switch” in Word
The second way to cajole Mail Merge into displaying numbers from Excel correctly is to modify the Word document. Specifically, this means applying the desired number format code to the Merge Fields in the Word document. (The merge fields basically tell the Word document which column in the Excel table has the desired data.) To apply a format to a field, you must include a numeric switch (formerly called a picture switch) in the field’s field code.
The first thing you have to do is to see the actual field code. Open the Mail Merge document and click the Mailings tab at the top of the window. Be sure the Preview Results button is toggled off so that you can see the Mail-Merge fields. Then right-click a Mail-Merge field (such as «Donation») and choose the Toggle Field Code option. You should now see the actual field code for that field, which is designated by curly braces as in { MERGEFIELD Donation }. Now edit the field code by simply inserting a numeric switch code to the end of the field code, as in
{ MERGEFIELD Donation \# $#,##0.00 }
There are many picture codes available. Here are four examples with their respective results:
{ MERGEFIELD Cost \# 00.00 } 01.00
{ MERGEFIELD Sales \# $### } $ 15
{ MERGEFIELD Sales \# $#,##0.00 } $ 1,500.00
{ MERGEFIELD Date \@ "MMMM d" } November 26
As you can see, the numeric switch codes are identical to the Excel formatting codes except that they are preceded by “\#” for numbers and “\@” for dates. (Note the use of quotation marks in the date code but not in the number codes.) To see more of the codes available, refer to the table below, or see the online help for “numeric switch” in Microsoft Word.
Here are some examples of how the numeric field codes work with data in a column labeled “Sales” in an Excel spreadsheet.
Numeric Switches for Mail-Merge MergeFields
In light of the fact that Word and Excel use the same formatting codes, we could not help wondering why they don’t use the same function format. For example, why not have the MergeField function look something like:
{ MERGEFIELD(Donation,"$#,##0.00") }
Good question. You’ll have to ask Microsoft.
Note: Before you start cursing me out, try to remember that when you add or change a numeric switch, the effect may not be shown immediately. You either have to update the field (right-click it and choose Update Field), or click the button Mailings > Preview Results. On one occasion I had to do this 2 or 3 times. If you are using the Mail-Merge Wizard, you may have to go back a step and return to see the effect of your changes. (Why? Again, you will have to ask Microsoft.)
The numeric switches in merge fields work well, but I find the process very difficult to remember. (“Is it a forward slash or a back slash?”) Also, it is very easy to make a mistake. Fortunately, for some users there is another way:
3. Use a DDE Link
The above approaches are relatively simple, but if you have more than a few fields that require formatting, they can drive you into early retirement. At the very least, they require you to remember format codes that, while similar, are used in very different ways.
A much more elegant and simple solution is to have Word link to the Excel workbook via a DDE (Dynamic Data Exchange) link rather than the usual, presumably non-dynamic, linking process. That sounds a little daunting, but if you are smart enough to do Mail Merge, then DDE can a piece of cake. It is a simple two-step process, and the first step — enabling Word to open a file via DDE — has to be done only once.
[Warning: Does DDE work in Office 2016 or 2019? Dynamic Data Exchange is an old technology, and it looks like Microsoft is in the process of pulling the plug on it. Sometimes it works for me in these fairly new versions, but lately it rarely works.
One trick you could try is to be sure that the Excel data source is open before you access it from Word. As usual for Excel data sources, the table must begin on the first row of the first worksheet in the workbook file. If you do this, and have some patience, you should be able to get it to work. But, beware: It may not work all the time.]
To set up Word for DDE links, do the following:
- Click: File > Options.
- Click the Advanced tab on the left and scroll down to the section General.
- Check the box labeled Confirm file format conversion on open.
That’s all for the first step, and you never have to do it again. From now on, your copy of Word can open up many different types of files, and can open these by different avenues, including DDE. 
The only side effect of the above is that every time you open a non-Word file with Word, the program will give you a chance to change your mind. No problem.
The second and last step has to be done each time you select a data source for your Mail Merge operation (either in Step 3 of Word’s Mail Merge Wizard or after you press the Select Recipients button in the Mailings ribbon). Relax. It is just three additional mouse clicks:
- After you have chosen the data file you would like to use, a new “Confirm Data Source” dialog box will appear.
- The default type of link is by OLE, but that is not what you want.
In the Confirm Data Source dialog box, click the check box to Show all.- In the expanded list of file types, choose MS Excel Worksheets via DDE (*.xls). (Choose this even if you are using the newer Excel file format: *.xlsx.)
- If asked, confirm that you are selecting the Entire Spreadsheet.
If you have already selected a spreadsheet for your Word document, you may have to select it again, this time via a DDE link. That’s it! From now on, your Excel formatting will travel over to Word Mail Merge documents fairly intact. One huge caveat here: Make sure that the data you want to merge are in the first sheet of your Excel workbook. (It took us two hours to finally figure out that DDE does not see anything but the first Excel worksheet!)
It is a shame that Microsoft has not replaced DDE with a new technology that works in a similar manner. When DDE worked, it was marvelous. Let’s hope an equally marvelous technology will appear in the near future.
Does DDE work for you in Word 2016 or 2019? If you have a comment about that or any other issue related to Mail Merge number formatting, please let me know. Click here to post an anonymous comment.
The Mail Merge process basically involves taking two files and merging them together. The first file is a letter, which is a basic word document. The second is a list of recipients. This list could be a table in Microsoft Word, but most often it is a worksheet in Excel. In this example, we will use an Excel spreadsheet and a simple letter that has already been created in Word.
4. Choose the Document Type
7. Write the Letter
Next, we have to add the salutation or greeting line. Delete the text now in the salutation and click the Greeting line option in the task pane on the right. A dialog box will appear asking you to confirm the structure of the salutation. Because this is a business letter, we need to change the punctuation to a colon. Click the list arrow at the right near the comma and change it to a colon. Then click OK.
In this step, we have added two merge fields. Be sure there is a blank line below each merge field. It looks a little cryptic right now, but that will soon change—as soon as you click Next: Preview your letters.
Prepare to be amazed: In this step, the merge fields have been replaced with actual data. You can use the arrow buttons to move forward or backward in your recipient list to see how each of the letters will appear. If you see any mistakes regarding line spacing or word spacing in the salutation, this is a good chance to fix that. Assuming that everything looks fine, let’s go on to the next step. Click Next: Complete the merge.
If you’re the more cautious type like me, the better choice is: Edit individual letters. This creates a new document which is composed of all the individual letters that are created in the Mail Merge process. We can now go through this batch of letters and correct any mistakes. We could also add a little personalization to a particular letter, for example, “I enjoyed seeing you at the park last week.” After we make our choice, Word will ask you to confirm that you want to print all the letters, which you usually want to do.