Area code
Area code 312 — Chicago, IL
Illinois · in service since 1947
Area code 312 covers Chicago, IL. It is an overlay: 872 serves the same area, so neighbors can have different area codes.
Overlay, same area: 872
Local time in Chicago
Spam reports from Sep 23 – Oct 22, 2026
Average #223 of 461 codes
423 FTC complaints
Consumer reports, not verified by the FTC.
See the reports- Time zoneCentral Time
- Local calls1 + 10 digits
- Prefixes798 assigned
- Runs out~1Q 2049
- Unwanted call?Block & report
Spam call reports about 312 numbers
Complaints by week
Sep 11 – Oct 22, 2026Show as table
| Week starting | Complaints |
|---|---|
| Sep 7 (3 days) | 21 |
| Sep 14 | 102 |
| Sep 21 | 118 |
| Sep 28 | 83 |
| Oct 5 | 85 |
| Oct 12 | 99 |
| Oct 19 (4 days) | 79 |
Compared with all codes
- Robocalls
- 56%all codes 75%
- Callers with the same code
- 41%all codes 35%
- Rank by complaints
- #223of 461 · middle half
- FCC complaints, Oct 2025 – Sep 2026
- 9513 about text messages
What the calls were about
Sep 11 – Oct 22, 2026
| Subject | Complaints | |
|---|---|---|
| Dropped call or no message | 121 21% | |
| Reducing your debt (credit cards, mortgage, student loans) | 58 10% | |
| Calls pretending to be government, businesses, or family and friends | 52 9% | |
| Medical & prescriptions | 33 6% | |
| Home improvement & cleaning | 8 1% | |
| Energy, solar, & utilities | 6 1% |
Where the people who complained live
Sep 11 – Oct 22, 2026
| State | Complaints | |
|---|---|---|
| Illinois | 379 65% | |
| California | 19 3% | |
| Virginia | 19 3% | |
| Florida | 14 2% | |
| New Jersey | 12 2% |
October 2026 (partial) report · most reported
Consumer reports, not verified by the FTC · source
Source: FTC Do Not Call complaints created Sep 11 – Oct 22, 2026. They are reported by consumers and are not verified by the FTC; caller ID can be spoofed (how we count).
Source: FCC Consumer Complaints data, unwanted calls filed Oct 1, 2025 – Sep 30, 2026, by caller ID; not verified by the FCC.
Area code 312 location and prefixes
| Exchange (NANPA) | Place | County | Prefixes |
|---|---|---|---|
| CHICGOZN01 | Chicago | spans 2 counties | 746 |
| WHEELING | Wheeling | spans 2 counties | 12 |
| HINSDALE | Hinsdale | spans 2 counties | 11 |
| LA GRANGE | La Grange | Cook County | 8 |
| NORTHBROOK | Northbrook | Cook County | 3 |
| ROSELLE | Roselle | spans 2 counties | 2 |
| CHICGOZN04 | Chicago | spans 2 counties | 1 |
| CHICGOZN07 | Chicago | spans 2 counties | 1 |
Source: NANPA CO codes of Oct 23, 2026; places: U.S. Census Bureau, matched by DialWhere (how).
NANPA record
- Location
- Illinois
- Assigned by NANPA
- 1947
- Local dialing
- 1 + 10 digits (NANPA: 1+10D)
- NANPA planning letters
- PL-392, PL-390, PL-195
Source: NANPA, NPA database of Oct 24, 2026.
Is 312 running out of numbers?
Previous forecast (October 2025): 2032, moved later by 17 years.
Forecast exhaust year by edition
Source: NANPA NRUF forecast, April 2026 edition.
Who holds 312 prefixes
The five largest of 37 original holders
As listed by NANPA, not today’s carrier.
| Holder (as listed) | Prefixes | |
|---|---|---|
| Illinois Bell Tel Co. | 334 42% | |
| New Cingular Wireless PCS, LLC | 82 10% | |
| T-Mobile USA, Inc. | 64 8% | |
| Verizon Wireless | 54 7% | |
| Mcimetro Access Transmission Services LLC | 40 5% |
Source: NANPA CO codes of Oct 23, 2026.
Questions about area code 312
What area code is 312?
An Illinois area code, in service since 1947.
Where is 312 area code, and what time zone is it in?
Chicago, IL; Central Time.
Why am I getting spam calls from 312?
423 FTC complaints from Sep 23 – Oct 22, 2026, most often about dropped calls or no message (not verified by the FTC; caller ID can be spoofed).
Will 312 get a new area code?
NANPA forecasts exhaust in 1Q 2049; no relief planning listed.