Results appear in red vs black

[tonifig8]

Can someone please help? How do I format my cell to automatically appear in red when, for example, a goal I set isn't reached so I want it to turn red indicating that that result is poor. Example, my goal is 100% (which appears in black), but when that goal isn't at 100% the result appears in red.
hope you can understand!

 

[barry houdini]

You can use conditional formatting....

Format > Conditional formatting

Use "Cell is" and "less than" and type 1 in the box, selct red formatting, OK

[Note: less than 1 because 100% = 1 in excel]

 

[tonifig8]

THANK YOU !!! THANK YOU!! THANK YOU!!!

 

[Scott Huish]

If you just want the font to appear red, you could use a custom number format of:

[Red][<1].00;General