How do you know if you're making a phone call outside of your local area?

Phone calls made to landline phone numbers starting with a different three-digit area code than the number of the phone line initiating the call are likely to be placed outside of the phone's local area. Some exceptions to this rule exist for overlapping area codes and certain regional calls.

Many heavily-populated areas of the United States have multiple area codes that are not geographically distinct. In most cases, calls to numbers within area codes of this type are not considered long-distance calls, though it is still necessary to dial the complete 10-digit phone number when making calls. Conversely, some phone calls are considered regional toll calls even within the same area code.