Excel 2003 users must use the formula solution. If you want to apply the conditional formatting technique, you must have Excel 2007 or later.
Free sample Excel worksheets are provided as an educational tool in support of this pro tip.
The rules
Knowing the rules and their precedence is imperative. Trying to apply ordinals without knowing the following rules will just make you sad:
 Values ending in 0 always get th.
 Values ending in 1 get st unless the value is 11 or a value that ends with 11.
 Values ending in 2 get nd unless the value is 12 or a value that ends with 12.
 Values ending in 3 get rd unless the value is 13 or a value that ends with 13.
 Everything else gets th.
Getting the rules applied in the correct order is the key. The values 11, 12, and 13 certainly throw a monkey wrench into the works, but Excel can handle it.
Also read: 75 essential Excel tips
One formula
In the figure below, I've used a formula to combine a value and its appropriate ordinal indicator:
=value&IF(AND(MOD(ABS(value),100)>10,MOD(ABS(value),100)<14),"th",CHOOSE(MOD(ABS(value),10)+1,"th","st","nd","rd","th","th","th","th","th","th"))
This formula has been in use for a long time. If you try a shorter version, be sure to check the results for values ending with 11, 12, and 13 carefully. Most importantly, this formula returns a string, not a value; you can't refer to the results of the formula in mathematical equations.
Although long, the formula is simple. The first part of the formula accommodates values ending with 11, 12, and 13. The second part of the formula uses CHOOSE() to handle the rest. I suppose you could simplify both components, but I've never tried. This works, and I can't justify the time it would take to rethink it. It works with positive and negative integers, ignoring decimal components.
A conditional format
You can also use a conditional format. This method displays the indicator with the actual value rather than creating a new string. The original value remains a numeric value. You only change the way Excel displays that value.
You'll need six formulas instead of one; use the formulas listed in Table A.
Table A


















You must enter the above rules in their listed order. There are other routes and other formulas, but this route specifies each rule in ordinal precedence. If you use other rules, be sure to account for the application order, which can get messy  it isn't impossible, but it is more difficult to follow.
Now, let's apply the first rule to the values shown below:
 Select the data. In this case, that's A1:H20.
 In the Styles group on the Home tab, click Conditional Formatting.
 Choose New Rule.
 In the New Formatting Rule dialog, select the last option in the upper pane: Use A Formula To Determine Which Cells To Format.
 Enter the "th" rule for the 49 rule:
=AND(MOD(ABS(A1),10)>3,MOD(ABS(A1),10)<10)
 Click Format.
 Click the Number tab.
 In the Category list, select Custom.
 In the Type field, enter the custom code: 0"th"
You can skip that last step if you like. I'm also using color to highlight the formatted values. Doing so creates a nice visual trail to follow, but you probably won't want to apply color to the values you format in your own sheets. Click the Fill tab, choose a color, and click OK.
Click OK twice. This first rule adds th to values ending with the digits 4 through 9.
Repeat this process for the remaining rules, being careful to add them in the listed order. When you enter the rules for 1, 2, and 3, you'll notice that Excel also formats the values ending with 11, 12, and 13, which is incorrect. Don't worry because the final rule for 11, 12, and 13 will override the earlier rules where necessary.
Bottom line
Using conditional formats to apply ordinal indicators can be problematic. First, you must be careful to consider precedence when entering the rules. My way isn't the only way and it isn't the most efficient, but it is easy to follow. Second, if you're working with other conditional formats, you must continue to consider precedence. You can combine rules and use the Stop If True property appropriately when combining this set of rules with others. Next month, I'll show you how to add ordinal indicators to dates.
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Full Bio
Susan Sales Harkins is an IT consultant, specializing in desktop solutions. Previously, she was editor in chief for The Cobb Group, the world's largest publisher of technical journals.