How to extract digits only from formatted phone number string?

Question

I'm getting user submitted phone numbers in a variety of forms, for example (fictional):

(423)700-4000
9002570000
703-203-3000

I want to extract just the numbers so that I can upload them to an app that doesn't accept anything but numbers. How can I do that with a Google Sheets formula?

Answer 1

This function gets rid of all non-digit characters from cell A1 with REGEXREPLACE(). To avoid error when there's no non-digit character, the formula is wrapped with a fall-back IFERROR(). Output strings are then cast as a number with VALUE().

=VALUE(IFERROR(REGEXREPLACE(A1,"[^0-9]",""),A1)

The output for the sample from above is:

4237004000
9002570000
7032033000