<div>
I would format all empty cells to 0%, then use conditional formatting to say all cells that equal 0% need to be red, for example.
</div>


<div>
You could set the cell format to percent which will automatically put the percent sign in if that is what you are trying to do.
</div>


<div>
<div class="content wysiwyg-content">
I need add a conditional formatting in Column B to reminder the user who forget to enter % for that Class Code. &nbsp;Need help for it.<br />
<br />
<br />
Column A &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Column B &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Column C<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
Class Code &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp; &nbsp;Percent<br />
0005 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 20%<br />
0016 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; please enter % &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
<br />
<br />
Thanks!
</div>
</div>


I need add a conditional formatting in Column B to reminder the user who forget to enter % for that Class Code.  Need help for it.


Column A            Column B             Column C
		
Class Code		    Percent
0005		                       20%
0016	          please enter % 	


Thanks!

I would format all empty cells to 0%, then use conditional formatting to say all cells that equal 0% need to be red, for example.

You could set the cell format to percent which will automatically put the percent sign in if that is what you are trying to do.

conditional formating in Excel

Microsoft Excel topics include formulas, formatting, VBA macros and user-defined functions, and everything else related to the spreadsheet user interface, including error messages.