312 Area CodeChicago, IL
Area code 312 covers Chicago and nearby communities in Illinois, in the Central Time (CT) zone, home to about 2.7 million people. It overlays 224, 773 and 872, so the region uses several codes and every local call needs all ten digits.
Overview
- Major City
- Chicago
- State
- Illinois (IL)
- Timezone
- Central Time (CT)
- Current Time
- Overlay
- Yes – shares area with 224, 773, 872
Overview of the 312 Area Code
What is the 312 area code?
The 312 area code serves Chicago, Illinois, alongside other established area codes. When you see a 312 number, it indicates a local number within this geographic area.
Why was area code 312 created?
The 312 area code was introduced as an overlay to add numbers in Chicago once the existing area codes 224, 773, and 872 began to run out of available prefixes. It added a new supply of numbers without requiring current residents to change their existing digits.
Geographic Coverage of the 312 Area Code
The 312 area code serves Chicago and surrounding areas in Illinois. It operates within the Central Time (CT) time zone. It complements the coverage of area codes 224, 773, and 872. This area code covers several key cities, including:
- Chicago
Got a call from a 312 number? It came from Chicago, IL. Since 312 overlays with 224, 773, and 872, every local call in the region needs all ten digits to land on the right line.
Chicago Area Codes Overview
Chicago is served by multiple area codes, reflecting its telecommunications needs. The 312 area code operates alongside 224, 773, 872. Here are the area codes serving this region:
The introduction of the 312 area code helped prevent number exhaustion, ensuring a continuous supply of phone numbers across the geographic area.
What cities does area code 312 cover?
| City | State | Population | % of Area Code | % of City |
|---|---|---|---|---|
| Chicago | IL | 2,721,308 | 100% | 8% |
* Sources: Population – U.S. Census Bureau PEP, Vintage 2024 (SUB-IP-EST2024-POP). Area code assignments – NANPA CO Code data. See our data methodology.
Has area code 312 been reported for unwanted calls?
Yes – 440 unwanted-call complaints were reported to the FTC for numbers showing a 312 area code (May 29 – Jul 2, 2026).
- 54% robocalls
- ↓ 2% vs prior period
Most-reported subjects
- Other46%204
- Calls pretending to be government, businesses, or family and friends12%51
- Dropped call or no message10%46
* Caller ID is easily spoofed, so these figures reflect the number shown on caller ID, not the caller's true location – an area code alone never identifies a caller. The FTC does not verify the facts in these complaints. Source: FTC Do Not Call (DNC) Reported Calls Data, retrieved 2026-07-05.
Which prefixes and exchanges belong to area code 312?
78% assigned to a telco
- 70% Landline
- 30% Wireless
- 0% Unknown
| Prefix | Usage | Carrier |
|---|---|---|
| (312)200- | Landline | Metropcs |
| (312)201- | Landline | Illinois Bell Tel Co |
| (312)202- | Landline | Illinois Bell Tel Co |
| (312)203- | Wireless | New Cingular Wireless Pcs |
| (312)204- | Landline | Illinois Bell Tel Co |
| (312)205- | Landline | Mcimetro Access Transmission Services |
| (312)206- | Wireless | New Cingular Wireless Pcs |
| (312)207- | Landline | Illinois Bell Tel Co |
| (312)208- | Wireless | New Cingular Wireless Pcs |
| (312)209- | Wireless | Verizon Wireless |
Frequently Asked Questions about the 312 Area Code
Who called me from a 312 number?
A 312 number is assigned to Chicago, Illinois, so a call may come from there. But caller ID is easy to fake, and scammers often spoof a local 312 code to look nearby, so a 312 number doesn't prove the caller is local. Recently, 440 unwanted-call complaints were reported to the FTC for numbers showing the 312 code (54% flagged as robocalls). If you don't recognize the number, let it go to voicemail; a real caller will leave a message.
Is 312 a scam area code?
No area code is a scam on its own. 312 is a normal, officially assigned code for Chicago, Illinois. Spam callers spoof local codes to raise the odds you answer, so 312 on your caller ID says nothing about who is really calling. Recently, 440 unwanted-call complaints were reported to the FTC for numbers showing the 312 code (54% flagged as robocalls). Judge the call itself, not the area code.
Why do I keep getting calls from the 312 area code?
Repeated calls from different 312 numbers are usually spoofing: a robocaller rotates through 312 numbers so each call looks local and slips past simple blocks. Recently, 440 unwanted-call complaints were reported to the FTC for numbers showing the 312 code (54% flagged as robocalls). Blocking one number rarely helps; voicemail screening, your carrier spam filter, and the Do Not Call Registry work better.
Should I answer an unknown 312 number?
If you aren't expecting a 312 call, let it ring to voicemail. Legitimate callers leave a message, most robocallers hang up when no one picks up, and answering can mark your number as active and bring more calls.
How do I block calls from the 312 area code?
Block a single 312 number from your recent-calls list (iPhone: tap the number, then Block this Caller; Android: tap the number, then Block or report spam). To cut the volume, turn on Silence Unknown Callers on iPhone or spam protection on Android, enable spam filtering from your carrier, and register at DoNotCall.gov. Blocking the entire 312 code also stops legitimate local calls, so use it only as a last resort.
Where is area code 312?
Area code 312 covers Chicago and the surrounding area in Illinois, spanning 1 city with about 2,721,308 residents. It shares its area with overlay codes 224, 773, 872.
Is 312 a real area code?
Yes. 312 is an active code in the North American Numbering Plan, assigned by NANPA and in service for Chicago, Illinois. A real code can still show up on spoofed spam calls, so treat unknown 312 calls with normal caution.
What timezone is the 312 area code in?
The 312 area code is in the Central Time (CT). Because a number can be kept when someone moves or switches to VoIP, a specific 312 caller may not be in that zone.
How do I call a 312 number from abroad?
From outside the US, dial your country's exit code, then 1 (the US country code), then 312 and the seven-digit number. From a mobile phone you can usually just enter +1 312 followed by the number and let the phone add the exit code for you.