Dialing practice · Updated October 25, 2026
Ten-Digit Dialing for US Local Calls
Learn when to include the area code, why overlays and 988 changed dialing, and how to update business phone records safely.
Ten-digit dialing means entering the three-digit area code followed by the seven-digit telephone number. You include the area code even when calling another number in your own area. It does not mean that every call is long-distance, and it does not change the number assigned to the subscriber.
The FCC’s ten-digit dialing guide explains the distinction and the transition associated with 988. A business should store complete numbers and check its service’s dialing instructions rather than assume that an old seven-digit contact still works.
Overlays made the area code essential
An overlay puts more than one area code over the same geographic region. Two subscribers can have the same seven local digits under different area codes. Dialing only those seven digits no longer identifies the complete destination, even if both subscribers are nearby.
This is why a newer area code can be local to the same neighborhood as an older one. The extra digits do not make the call less local. They identify the correct destination. See how area codes and overlays work for the difference between an overlay and a geographic split.
Do not apply one city’s rule to an entire state. A state can contain several independent numbering regions, some with overlays and some without. The directory records overlay history at the code level so that these differences remain visible.
The 988 transition was a separate reason
The United States adopted 988 as the short code for the Suicide & Crisis Lifeline. In affected areas that previously permitted seven-digit dialing and used 988 as the first three digits of local numbers, dialing had to change so that the short code could be recognized correctly.
That means an area without an overlay can still require ten-digit local dialing. Counting a state’s codes is not a reliable way to determine the rule. The FCC describes the affected-area transition; do not generalize it into a claim that every historical seven-digit arrangement changed for the same reason.
Service codes remain distinct from ordinary subscriber numbers. Do not prepend an area code to 911 or 988 when using those services in the United States. Do not use either number to test a business phone system or a newly rented inbound number.
Ten digits, 1 plus ten digits, and +1
The national number consists of an area code and seven local digits. A leading 1 may also be required by a particular fixed-line service. The FCC notes examples of areas where that extra digit may be needed for local calls. Follow the instructions for the line or phone system you actually use.
For international contact records, +1 followed by the ten-digit number is the usual representation. The plus sign represents the international dialing access method on a supported device; it is not a digit in the subscriber number. A phone that cannot interpret the plus sign may require a country-specific international access prefix.
Do not automatically strip the leading 1 from a dial plan, or automatically add another one to numbers that already contain it. Importing a mixture of national and international formats without validation can produce duplicate prefixes or ambiguous destinations.
Update more than your address book
A dialing change can affect devices and workflows that people rarely inspect. Review speed-dial entries, fax settings, forwarding rules, appointment reminders, phone-system directories and any equipment that dials a stored telephone number. For alarms or other safety-related equipment, use the equipment supplier’s approved update and testing process.
Create a small sample set before changing every record. Include a number in the same area code, one in a different area code, and a known international destination if your service supports it. Test the approved formats and review call records to confirm the intended destinations were reached.
Do not alter customer-supplied numbers blindly. Keep the original value where your business process requires an audit trail, normalize a separate dialing field, and flag ambiguous entries for review. A missing area code is missing information, not permission to guess based on the customer’s current address.
What to put on your website
Publish the complete number, including its area code. If international callers are expected, present the +1 format clearly and make the telephone link match the displayed destination. Avoid publishing a seven-digit abbreviation that only some local callers can interpret.
Then test the actual link on a phone and check that the right team answers. Number formatting, call routing and opening hours are separate checks. A perfectly formatted telephone link can still lead to an outdated destination, so revisit it whenever the service or staffing changes.