Starting October 7, 2025, residents and businesses in Detroit's 313 area code must use 10-digit dialing for all local calls.

This change is in preparation for the new 679 overlay area code, set to be introduced on November 7, 2025.

During the six-month permissive dialing period that began on April 7, callers could use either seven or 10 digits.

However, after October 7, seven-digit calls will not be completed.

Existing 313 numbers will remain unchanged.

The 679 area code will be assigned to new numbers once 313 numbers are exhausted, projected to occur in the fourth quarter of 2027.

To avoid disruptions, residents should update devices and services programmed for seven-digit dialing, including medical alert systems, security systems, and contact lists.

Emergency services like 911 and 988 will remain accessible via three-digit dialing.

For more information, contact your telephone service provider or visit the Michigan Public Service Commission's website.