Quick answer
Area code 313 serves Detroit and most of its closest suburbs in Wayne County. Cities in it include Detroit, Dearborn, Hamtramck, Highland Park, Allen Park and Dearborn Heights. This guide covers where 313 is, how it came to be, how to dial it and what to know before using a 313 number for a business.
- Area code 313 serves Detroit and most of its closest suburbs in Wayne County, Michigan.
- It is one of the original area codes of 1947 and is often seen as shorthand for the city of Detroit.
- Splits took the area north to 810 in 1993 and west to 734 in 1997, so 313 is now much smaller.
- Area code 679 became an overlay on November 7, 2025, so ten-digit dialing is now mandatory.
Where is area code 313?
Area code 313 covers Detroit and most of its closest suburbs in Wayne County. Cities in the area include Detroit, Dearborn, Dearborn Heights, Hamtramck, Highland Park, Allen Park, Ecorse, Harper Woods, Inkster, Melvindale, Lincoln Park and Redford. In Taylor, the boundary runs north of Goddard Road and east of Holland Road.
It was not always this small. The 313 area once reached far beyond Detroit, and Ann Arbor, for example, moved to a different area code in the 1990s. Today 313 is a compact urban code, which is part of why it carries so much identity for Detroiters.
| City | Where it is |
|---|---|
| Detroit | The city most associated with 313 |
| Dearborn | Wayne County |
| Hamtramck | An enclave surrounded by Detroit |
| Highland Park | An enclave surrounded by Detroit |
| Allen Park | Wayne County |
| Inkster | Wayne County |
313 area code history
The code has a short, well-documented history. These are the dates that matter:
| Date | What happened |
|---|---|
| October 1947 | Area code 313 is assigned as one of the original 86 area codes, serving the south-eastern part of Michigan. |
| December 1, 1993 | The northern part splits off as area code 810. |
| December 13, 1997 | The western part, including Ann Arbor, splits off as area code 734. |
| February 2000 | Area code 679 is reserved as an overlay, but the relief schedule is cancelled in April 2000. |
| April 7, 2025 | Permissive ten-digit dialing begins ahead of the new overlay. |
| November 7, 2025 | Area code 679 enters service as an overlay, and ten-digit dialing becomes mandatory. |
How to dial
Since the 679 overlay, every call in the 313 area must be dialed with ten digits, whether you are calling next door or across Wayne County. The permissive period ran from April 7 to October 7, 2025, after which seven-digit local dialing stopped working. Calls from elsewhere use 1 + the area code + the seven-digit number.
If your business has old equipment, such as alarm dialers, gate boxes or speed-dial lists, check that each stored number includes 313 or 679. New numbers in the area may now start with either code, so do not assume that a caller from Detroit has a 313 number.
Will the area code change?
Area code 313 was projected to run short of numbers for years. A 2021 estimate expected exhaustion in 2025, and a later extension moved the threshold to the first quarter of 2028, which is why the 679 overlay was activated. The 679 overlay now supplies new numbers in the same area, and no further change is currently planned.
Time zone and business hours
Detroit and Wayne County observe Eastern Time, the same as New York. Calls to a 313 number made at 9 AM Eastern reach businesses as they open, and the same hour is 6 AM in Los Angeles, so west-coast teams should plan early calls.
Using a 313 number for business
A 313 number carries real weight in Detroit. Because the code is so tightly linked with the city, local businesses, restaurants, repair shops and service companies often prefer it to a number from a neighbouring code. Today, a new line may come from 313 or 679, so check which codes you can get when you sign up.
Ringflow lets you run a 313 number on mobile and desktop with call forwarding, voicemail-to-email, an auto-attendant and two-way text messaging. Porting an existing 313 number is free, and there is a 14-day free trial. Availability depends on the area code, so confirm it before you plan a launch.
If you also work in nearby areas, see our guides to area code 248 and area code 616, or read how a virtual phone number works and how to add a second business number.
Spam and scam calls
Spoofing makes it easy for scammers to show a Detroit number on your screen. If a caller claims to be from a bank, a utility or a government agency, hang up and call the organisation back on a number from its official website. Report scam calls at reportfraud.ftc.gov, and add your number to the National Do Not Call Registry at donotcall.gov.
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FAQ
Area code 313 serves Detroit and most of its closest suburbs in Wayne County, Michigan, including Dearborn, Hamtramck, Highland Park and Allen Park.
Area code 679 is an overlay on 313 that went into service on November 7, 2025. Ten-digit dialing is mandatory.
No. Ann Arbor moved to area code 734 in the 1997 split.
It has been Detroit's area code since 1947 and is often used as shorthand for the city.
Eastern Time.
