To determine if a phone number is available, an individual can contact a phone company within the desired area code to check the availability. Online sites specializing in vanity phone numbers for businesses or individuals may also offer a search tool to determine if a phone number is in use.
When contacting a local or national phone company, indicate the number desired, and specify the area code or if an 800, 866, or 877 prefix is preferable. Some phone companies may not release this information, though, if the phone number is not part of their jurisdiction. It may be necessary to contact several different phone numbers to verify if the number desired is available.