Conditional formatting for specific phone number format

Hi all,

I want to see all phone numbers that are not in this format ###-###-#####, to get highlighted.

Ideally I'm looking for a conditional formatting rule that will check the phone format, and if it's not in this format ###-###-#####, highlight the cell.

Phone #.xlsx

The attachment has two columns, one with plain data and the other showing what I would want the conditional formatting to do (however in my sheet this has been completed manually by inserting a fill)

Thank you so much in advance!

Highlight A2:A12 > Conditional Format > New Rule > Use a formula
=NOT(COUNTIF(A2,"???-???-????"))
Format: Fill yellow > OK > OK

Thank you for your help! I added this and it worked for some....but also missed mis-formatted others.

Any idea why?

For example, 777-777-7777 is a correct format but is being marked yellow. 000-000-00 is incorrect format but is not being marked as yellow.
Phone #.xlsx

The Conditional Formatting Rules Manager suggests that you did not apply the formula the same way as was suggested in post #2.

You applied it to the entire column A (which starts with cell A1).

If you want to do this, change the formula to:
=NOT(COUNTIF(A1,"???-???-????"))

If you want to apply the CF to the entire column and don't want to highlight blank cells, you can use this:
=AND(A1<>"",NOT(COUNTIF(A1,"???-???-????")))

Awesome! Thank you so much for your help!!

Happy to help. Thanks for the rep.