---
title: "Area code 313: Michigan, United States"
url: "https://lookvalid.com/area-code/313.md"
canonical_url: "https://lookvalid.com/area-code/313"
last_updated: "2026-10-23"
type: "reference"
summary: "Area code 313 serves Michigan, United States. Number formats, numbering rules, a live phone validator and the other codes in Michigan."
---

# Area code 313: Michigan, United States

Area code 313 serves Michigan, United States. Number formats, numbering rules, a live phone validator and the other codes in Michigan.

NANPA lists 766 central office codes (prefixes) in use in area code 313, held by 35 holders across 6 rate centers.
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.
The FCC unwanted-call data has 3,076 complaints on file for 1,987 numbers in 313, most often filed as "Unwanted Calls". These are consumer reports, not findings.

## Facts

- 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

| Rate center | Prefixes | Share |
| --- | --- | --- |
| DETROITZN5 | 271 | 35% |
| DETROITZN6 | 153 | 20% |
| DETROITZN1 | 152 | 20% |
| DETROITZN4 | 71 | 9% |
| DETROITZN2 | 69 | 9% |
| DETROITZN3 | 50 | 7% |

## Carriers

| 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.

## History

- 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

3,076 complaints for 1,987 numbers. Numbers whose latest complaint falls in each year:

- 2023: 91
- 2024: 134
- 2025: 119

## Questions

### 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.

Sources: NANPA central office code report dated 2026-10-17; NANPA NPA report dated 2026-10-18; FCC unwanted-call complaints, data fetched 2026-10-17; ZIP code places from GeoNames (CC BY 4.0).