10-digit dialing required in 313 area code starting Oct. 7

News media contact: Matt Helms 517-284-8300  

Customer Assistance: 800-292-9555  

Beginning Oct. 7, all local calls made by customers within the Detroit area’s 313 area code must be placed using 10 digits – including both the area code and a 7-digit telephone number – as the area gets ready for a new overlay area code.

Starting that day, any local calls placed using just seven digits, without an area code, will not be completed.

This is the final phase of the implementation of a new 679 area code in metro Detroit, as the area’s long-serving 313 area code is running out of available numbers to assign to new customers. An important note: Current 313 area code customers will not have to change their phone number and will be able to keep the 313 area code. The new 679 area code will apply to new phone numbers issued once the 313 area code’s numbers run out.

As part of the transition to having two area codes, all local calls dialed in the 313 area code must use 10-digit dialing. The MPSC in March announced a six-month permissive dialing period during which callers in the 313 area code were urged to practice using 10-digit dialing for every call. As of Oct. 7, seven-digit dialing will no longer be optional. An area code will be required for every local call.

The transition is part of the preparations for the 679 area code to begin operating in Detroit and its nearby suburbs: Allen Park, Dearborn, Dearborn Heights, Ecorse, the Grosse Pointes, Hamtramck, Highland Park, Inkster, Lincoln Park, Redford Township, River Rouge and Taylor.

Starting on Nov. 7, customers in the 313 area code may be assigned a number with the new 679 area code when they request new service or an additional line. However, numbers with the new 679 area code will only be assigned to new customers once telephone numbers in the 313 area code have been exhausted. The exhaust date is currently projected to be the first quarter of 2028, but the timing is subject to change due to telephone numbering demand.

Here are key facts to know about the new area code:

•        Existing telephone numbers, including the current area code, will not change.
•        If you seek new phone service on and after Nov. 7, 2025, you may be assigned a phone number with the 679 area code.
•        You will need to dial the area code and telephone number for all local calls, including calls within the same area code.
•        You will continue to dial 1 plus the area code and the telephone number for all long-distance calls.
•        The price of a call, coverage area, or other rates and services will not change due to the added area code.
•        What is a local call now will remain a local call, and long-distance rates will not be charged for local calls.
•        Customers can still dial just three digits to reach 911 and 988, as well as 211, 311, 411, 511, 611, 711 and 811 if those are currently available in their community.

Please remember to identify your telephone number as a 10-digit number and include the area code when giving the number to friends, family, business associates and customers, etc.

Customers should ensure all services, automatic dialing equipment, applications, software, or other types of equipment are reprogrammed to dial 10 digits if they are programmed to dial just 7 digits currently.  Examples include life-safety systems, fax machines, internet dial-up numbers, gates, speed dialers, mobile phone contact lists, call forwarding settings, voicemail services, and similar functions.

Be sure to check business stationery, advertising materials, personal checks, and your personal or pet ID tags to ensure the area code is included with your telephone number.

Important safety and security equipment, such as medical alert devices, and alarm and security systems must be programmed to use 10-digit dialing.  Many systems operate on 10-digit dialing by default, but some older equipment may still use 7 digits.  Please contact your medical alert or security provider if you are not sure whether your equipment needs to be reprogrammed to accommodate the upcoming change to 10-digit local dialing.  Any needed reprogramming of alarm and home security equipment must be done before Oct. 7, 2025.

Remember that all local calls must be programmed using 10 digits and add ‘1’ for all long-distance calls.

For more information, please contact your local telephone service provider or visit the Michigan Public Service Commission’s webpage on numbering.

For information about the MPSC, visit www.michigan.gov/mpsc, sign up for its monthly newsletter or other listservs. Follow the MPSC on Facebook, X/Twitter or LinkedIn.

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