Area code
313
313 is a United States area code. Under the North American Numbering Plan it belongs to Michigan, which has 13 area codes in total.
Validate a number in 313
Paste a full number and the tool checks it against the numbering plan. It returns the standard formats, the line type the plan assigns and the area code region.
Digits with or without punctuation work. Numbers outside the US are read with the +country code.
Area code 313 at a glance
NANPA lists 766 central office codes (prefixes) in use in area code 313, held by 35 holders across 6 rate centers.
| Fact | Value |
|---|---|
| In service since | 1947-01-01 |
| Time zone | Eastern (E) |
| Assigned overlays | 679 (2025-11-07) |
| Prefixes in use | 766 |
| Pooled prefixes | 482 (63%) |
| Rate centers | 6 |
| Companies holding prefixes | 35 |
| Assignment dates on file | 2001-03-09 to 2026-05-27 (220 prefixes) |
Rate centers in area code 313
| Rate center | Prefixes | Share |
|---|---|---|
| DETROITZN5 | 271 | 35% |
| DETROITZN6 | 153 | 20% |
| DETROITZN1 | 152 | 20% |
| DETROITZN4 | 71 | 9% |
| DETROITZN2 | 69 | 9% |
| DETROITZN3 | 50 | 7% |
Who holds the prefixes in 313
Michigan Bell Tel holds the most prefixes, 244 (32%). 63% of the prefixes are pooled, which means their thousands-blocks can belong to different companies.
| Holder | Prefixes | Share |
|---|---|---|
| Michigan Bell Tel | 244 | 32% |
| Omnipoint Communications Midwest Operations | 141 | 18% |
| New Cingular Wireless PCS | 92 | 12% |
| Verizon Wireless | 54 | 7% |
| Bandwidth.com CLEC | 28 | 4% |
| Mcimetro Access Transmission Services | 25 | 3% |
| 29 other carriers | 182 | 24% |
A prefix holder is the company a code was assigned to, not necessarily a number's current carrier, because numbers can be ported to another company. Find which carrier a number is on, or browse the prefix holders.
History of area code 313
- 1947-01-01 Area code 313 went into service.
- 1947-01-01 Area code 313, named as the parent of 313 in the NANPA report, was in service.
- 1947-01-01 Area code 313 went into service as an overlay in the same area as 313.
- 1993-12-01 Area code 810 went into service and names 313 as its parent.
- 1997-12-13 Area code 734 went into service and names 313 as its parent.
- 2025-11-07 Area code 679 went into service as an overlay in the same area as 313.
Complaints on file for 313 numbers
3,076 FCC complaints are on file for 1,987 numbers in 313, most often filed as "Unwanted Calls". These are unverified consumer reports.
| Year of latest complaint | Numbers |
|---|---|
| 2023 | 91 |
| 2024 | 134 |
| 2025 | 119 |
Other area codes in Michigan
Michigan is one state with 13 area codes in the NANPA table. 313 is one of them.
Next to 313 in the numbering table
These are the codes just before and after 313 when all are sorted by number. They are neighbours on the list, not necessarily on the map.
What the area code does and does not tell you
A number that starts with 313 was first assigned in Michigan. That is a fact about where the number began, and it is a useful hint when you check a form entry, for example a billing address in Michigan next to a 313 phone number.
It does not show where the person is today. A number stays with its owner after a move or a change of provider (number portability), and mobile numbers travel with the handset. The area code also cannot tell you whether the line is active, who the carrier is, or whether the number is mobile or fixed: the plan shares those ranges. Read more about the area code, the numbering plan and line type.
Check numbers in bulk with the API
| Product | Credits | Docs |
|---|---|---|
| Phone Numbering-Plan Validation | 1 credit per valid number | API docs |
| Phone Intelligence (carrier and line status) | 1 credit per check (invalid numbers outside the US and Canada are free) | Product page |
Questions about area code 313
Where is area code 313?
NANPA assigns area code 313 to Michigan, United States.
In which state does area code 313 sit?
Michigan. 313 is one of 13 area codes the NANPA table assigns to the state.
Who owns area code 313?
NANPA assigns area codes. Within 313, Michigan Bell Tel holds the most prefixes, 244 prefixes or 32%.
Which time zone does 313 use?
The NANPA NPA report lists the time zone for 313 as Eastern (E).
What year did 313 enter service?
The NANPA NPA report gives an in-service date of 1947-01-01, so 313 has been in use since 1947.
Does area code 313 have an overlay?
Yes. 679 (in service 2025-11-07) shares the same area with 313, so numbers from all of them are local to each other.
How many prefixes does area code 313 have?
NANPA's report dated 2026-10-17 lists 766 prefixes in service in 313, spread over 6 rate centers and 35 holders.
Are there complaints about 313 numbers?
The FCC data on file has 3,076 complaints for 1,987 numbers in 313. They are unverified consumer reports. A number with no complaints on file is not proven safe.
Area code assignments: North American Numbering Plan Administrator NPA report, file dated 10/17/2026, retrieved 2026-10-17. Source file. New codes are assigned several times a year. Prefixes, rate centers, holders, time zone, in-service date and overlays: NANPA central office code report dated 2026-10-17 and NPA report dated 2026-10-18. Complaints: FCC consumer complaints open data, fetched 2026-10-17. ZIP code places: Postal code places and coordinates: GeoNames (geonames.org), licensed CC BY 4.0.