312 Area Code: Chicago, Illinois
Area code 312 serves Chicago, Illinois in the Central time zone, in service since 1947. Consumers have filed 6,486 unwanted-call complaints against 3,885 different 312 numbers, 349 of them with the FTC in the last 30 days. Look up the exact number that called you below.
Area code 312 at a glance
- State
- Illinois
- Main cities
- Chicago
- Counties
- Cook County, DuPage County
- Local time
- —Central
- In service since
- 1947
- Overlay code
- 872 (2009)
- Local dialing
- 10 digits (area code + number)
- Exchanges
- 8 rate centers, 784 prefixes
Sources: NANPA area code and central office code records (refreshed weekly); cities and counties matched from US Census Bureau and USGS place names.
Most-reported 312 numbers
Ranked by FTC Do Not Call complaints this month, then all-time FTC and FCC complaints. Only numbers with enough complaints for a full report page are listed. Click one for what it was reported for and where.
What calls from 312 numbers are about
1,074 FTC Do Not Call complaints about 312 numbers since Jul 24. The most common named subject is debt-relief pitches, at 11% of complaints (50% of those were recorded messages). Overall, 54% of callers who answered said the call was a robocall.
FTC complaint subjects
- Other / unspecified50947%
- Dropped call / no message18717%
- Debt reduction11311%
- Impostor (government, business, family)1019%
- No subject given585%
- Medical & prescriptions495%
- Warranties & protection plans141%
FCC complaints by call type, last 2 years
- Text Message12441%
- Live Voice9331%
- Prerecorded Voice8628%
41% of recent FCC complaints about 312 numbers are about text messages, not calls.
When 312 spam calls come in
30% of complaints that give a call time describe calls between 9am and 12pm. 95% came Monday to Friday, most on Wednesdays, the pattern of call-center robocall campaigns that run on business hours. Times are as consumers reported them to the FTC.
By hour of the day
By day of the week
Is it getting worse?
407 FTC complaints about 312 numbers in the last four weeks, up 30% on the four weeks before. FCC complaints about 312 numbers peaked in 2018 (884); the FTC's daily Do Not Call data has carried most of the volume since mid-2026.
FTC complaints per week
FCC complaints per year
Years shown as '15 to '26; the current year is partial.
Who gets these calls
67% of the FTC complaints about 312 numbers came from Illinois residents, but only 37% from people with 312 numbers themselves. The calls are mostly regional rather than aimed at 312 phones specifically.
Where complainants live
- Illinois71667%
- California424%
- Florida293%
- Texas262%
- Ohio202%
What people with 312 numbers report
People whose own number starts with 312 filed 3,756 FTC complaints since Jul 24. 11% were about calls showing another 312 number. The most common named subject was debt-relief pitches.
Area codes on the calls they reported
- 312 (same code)39911%
- 833 (toll-free)2206%
- 877 (toll-free)1955%
- 888 (toll-free)1885%
- 866 (toll-free)1434%
Busiest 312 prefixes this month
FTC complaints in the last 30 days, grouped by the first six digits. When one prefix collects complaints about many different numbers, a campaign is usually cycling through that block. The carrier is who NANPA assigned the prefix to, not who made the calls.
| Prefix | Complaints | Numbers | Carrier | Exchange |
|---|---|---|---|---|
| (312) 283-xxxx | 20 | 13 | Level 3 (Lumen) | Chicago |
| (312) 748-xxxx | 15 | 14 | Onvoy (Sinch) | Chicago |
| (312) 682-xxxx | 11 | 11 | Nuso, LLC | Chicago |
| (312) 312-xxxx | 11 | 5 | Onvoy (Sinch) | Chicago |
| (312) 473-xxxx | 10 | 9 | Onvoy (Sinch) | Chicago |
Carriers operating in 312
NANPA has assigned 784 312 prefixes (NPA-NXX central-office codes) across 8 rate centers: 33% to wireless carriers, 67% to landline and VoIP operators; 53% are pooled blocks shared by several carriers. 2 prefixes were assigned in the last 12 months (newest 2026-01-29). The carrier holding a prefix is who the number was issued through. It says nothing about who is calling, since caller ID is routinely spoofed.
| Carrier | Type | Prefixes | Rate centers | Newest assignment |
|---|---|---|---|---|
| Ameritech (AT&T) | Incumbent landline (ILEC) | 334(43%) | 1 | 2012-10-19 |
| AT&T Mobility (New Cingular Wireless PCS) | Wireless | 82(10%) | 4 | 2017-07-31 |
| T-Mobile USA | Wireless | 64(8%) | 3 | 2019-01-30 |
| Verizon Wireless (Cellco Partnership) | Wireless | 54(7%) | 3 | 2017-10-19 |
| Level 3 (Lumen) | Competitive / VoIP (CLEC) | 33(4%) | 1 | 2018-07-12 |
| MCImetro (Verizon Business) | Competitive / VoIP (CLEC) | 33(4%) | 1 | 2017-04-28 |
| Spok, INC. | Wireless | 33(4%) | 2 | — |
| Teleport Communications America, LLC | Competitive / VoIP (CLEC) | 22(3%) | 1 | 2017-10-20 |
| Onvoy (Sinch) | Competitive / VoIP (CLEC) | 20(3%) | 1 | 2026-01-27 |
| American Messaging Services, LLC | Wireless | 14(2%) | 1 | 2001-04-23 |
| PAETEC (Windstream) | Competitive / VoIP (CLEC) | 13(2%) | 1 | 2017-10-20 |
| Bandwidth.com | Competitive / VoIP (CLEC) | 12(2%) | 1 | 2017-07-20 |
Largest rate centers (exchanges) by prefixes: Chicago (748), Wheeling (12), Hinsdale (11), La Grange (8), Northbrook (3), Roselle (2). Source: NANPA Central Office Code Utilized Assignments (public, refreshed weekly).
What to do about calls from 312 numbers
Before you call back
- Debt reduction is the top named complaint here. Don't pay upfront fees for debt relief; the FTC's Telemarketing Sales Rule bans them. Talk to your lender or a nonprofit credit counselor instead. Read about debt-relief robocalls.
- Look up the full number above. A missed call from 312 with no voicemail is usually a robocall; anyone who needs you will leave a message.
- Block repeat callers: iPhone, Android, or your carrier's free filter (Verizon, AT&T, T-Mobile).
Report it in Illinois
- Unwanted sales calls and robocalls: donotcall.gov (FTC). Scams and fraud: ReportFraud.ftc.gov.
- Spoofing, texts and call-blocking problems: FCC consumer complaints.
- State complaints: Illinois Attorney General.
- Illinois formally adopted the FTC's National Do Not Call Registry as its own state list rather than running a separate one, so a single free registration at donotcall.gov covers you. State authorities can still enforce against telemarketers who ignore it, in addition to any federal penalty.
Your FTC and FCC reports are published (without your name or number) in the datasets this page is built from. How to report unwanted calls.
Area code 312: questions answered from the data
Where is area code 312?
Area code 312 serves Chicago, Illinois, covering Cook County and DuPage County. It has been in service since 1947.
What time zone is area code 312 in?
Area code 312 is in the Central time zone (UTC−6, or UTC−5 during daylight saving time). The current local time is shown at the top of this page.
Which area codes overlay 312?
872 (in service 2009) serves the same area as 312. New numbers there can be issued with any of these codes, and local calls need all 10 digits. A spoofed call can display any of them.
What are calls from 312 numbers usually about?
Since Jul 24, consumers filed 1,074 FTC Do Not Call complaints about 312 numbers. The most common named subject was debt-relief pitches: 11% of complaints, 50% of them recorded messages. Across all subjects, 54% of callers who answered the question said the call was a robocall.
When do 312 spam calls happen?
30% of the complaints that give a call time describe calls between 9am and 12pm, and 95% came on weekdays, most often on Wednesday. Times are as consumers reported them.
Are calls from 312 numbers really local?
Not necessarily. 67% of the FTC complaints about 312 numbers came from Illinois residents, but only 37% from people with 312 numbers themselves. The calls are mostly regional rather than aimed at 312 phones specifically.
Are 312 robocalls increasing?
In the four weeks to Oct 15, consumers filed 407 FTC complaints about 312 numbers, 30% more than the four weeks before.
How do I report a 312 scam call in Illinois?
Report unwanted sales calls and robocalls to the FTC at donotcall.gov, and scams to ReportFraud.ftc.gov. The FCC takes complaints at consumercomplaints.fcc.gov. In Illinois, the Illinois Attorney General also handles consumer complaints about scam calls. Reports feed the public data this page is built from.
Overlay and nearby area codes
Sources: FTC Do Not Call complaints (unverified consumer reports), published every weekday and available here from Jul 24; FCC Consumer Complaint Data, public record, imported nightly; NANPA numbering records. A number appearing here means consumers reported calls that displayed it. Caller ID can be spoofed.