Illinois, United States
Central Time
12:23 AM
Area Code
312
State / Province
Illinois
Country
United States
Time Zone
Central Time
Area code 312 covers 6 cities and communities across Illinois, based on telephone company rate center data.
Use the E.164 format for clickable phone links (RFC 3966):
<a href="tel:+13125550100">+13125550100</a><a href="tel:+13125550199">+13125550199</a>Look up which exchange in Illinois a specific 312 number is homed to, and whether its block is wireline or wireless. See what a reverse lookup can establish before relying on the answer.
784 active prefixes in this area code, assigned as 4,666 thousands-blocks — pooling splits one prefix across several carriers, so each block is listed separately with the rate centre it is homed to, its carrier of record, and the switch that serves it.
Showing blocks 1–100 of 4,666
| NPA-NXX | Block | Rate centre | Type | Carrier (OCN) | Switch | LATA | LIR | Dates |
|---|---|---|---|---|---|---|---|---|
| 312-200 | 0 | Chicago Zone 01-Calumet | Landline or VoIP | METROPCS, INC. (5562) | ELGNILOTGT5 | 358 | — | — |
| 312-200 | 1 | Chicago Zone 01-Calumet | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 312-200 | 2 | Chicago Zone 01-Calumet | Landline or VoIP | METROPCS, INC. (5562) | ELGNILOTGT5 | 358 | — | — |
| 312-200 | 3 | Chicago Zone 01-Calumet | Landline or VoIP | METROPCS, INC. (5562) | ELGNILOTGT5 | 358 | — | — |
| 312-200 | 4 | Chicago Zone 01-Calumet | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 312-200 | 5 | Chicago Zone 01-Calumet | Landline or VoIP | METROPCS, INC. (5562) | ELGNILOTGT5 | 358 | — | — |
| 312-200 | 6 | Chicago Zone 01-Calumet | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 312-200 | 7 | Chicago Zone 01-Calumet | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 312-200 | 8 | Chicago Zone 01-Calumet | Landline or VoIP | METROPCS, INC. (5562) | ELGNILOTGT5 | 358 | — | — |
| 312-200 | 9 | Chicago Zone 01-Calumet | Landline or VoIP | METROPCS, INC. (5562) | ELGNILOTGT5 | 358 | — | — |
| 312-200 | A | Chicago Zone 01-Calumet | Landline or VoIP | METROPCS, INC. (5562) | ELGNILOTGT5 | 358 | — | — |
| 312-201 | A | Chicago Zone 01-Franklin | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO FRANKLIN | 358 | — | — |
| 312-202 | 0 | Chicago Zone 01-Superior | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO SUPERIOR | 358 | — | — |
| 312-202 | 1 | Chicago Zone 01-Superior | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO SUPERIOR | 358 | — | — |
| 312-202 | 2 | Chicago Zone 01-Superior | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 312-202 | 3 | Chicago Zone 01-Superior | Landline or VoIP | ACCESS ONE, INC. - IL (5447) | CHCGILDTKMD | 358 | — | — |
| 312-202 | 4 | Chicago Zone 01-Superior | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO SUPERIOR | 358 | — | — |
| 312-202 | 5 | Chicago Zone 01-Superior | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO SUPERIOR | 358 | — | — |
| 312-202 | 6 | Chicago Zone 01-Superior | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO SUPERIOR | 358 | — | — |
| 312-202 | 7 | Chicago Zone 01-Superior | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO SUPERIOR | 358 | — | — |
| 312-202 | 8 | Chicago Zone 01-Superior | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO SUPERIOR | 358 | — | — |
| 312-202 | 9 | Chicago Zone 01-Superior | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO SUPERIOR | 358 | — | — |
| 312-202 | A | Chicago Zone 01-Superior | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO SUPERIOR | 358 | — | — |
| 312-203 | A | Chicago Zone 01-Wabash | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | BURGILAHGT3 | 358 | — | — |
| 312-204 | 0 | Chicago Zone 01-Superior | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO SUPERIOR | 358 | — | — |
| 312-204 | 1 | Chicago Zone 01-Superior | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO SUPERIOR | 358 | — | — |
| 312-204 | 2 | Chicago Zone 01-Superior | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO SUPERIOR | 358 | — | — |
| 312-204 | 3 | Chicago Zone 01-Superior | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO SUPERIOR | 358 | — | — |
| 312-204 | 4 | Chicago Zone 01-Superior | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO SUPERIOR | 358 | — | — |
| 312-204 | 5 | Chicago Zone 01-Superior | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO SUPERIOR | 358 | — | — |
| 312-204 | 6 | Chicago Zone 01-Superior | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | BENSENVILLE | 358 | — | — |
| 312-204 | 7 | Chicago Zone 01-Superior | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | BENSENVILLE | 358 | — | — |
| 312-204 | 8 | Chicago Zone 01-Superior | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | BENSENVILLE | 358 | — | — |
| 312-204 | 9 | Chicago Zone 01-Superior | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 312-204 | A | Chicago Zone 01-Superior | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO SUPERIOR | 358 | — | — |
| 312-205 | A | Chicago Zone 01-Calumet | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | BENSENVILLE | 358 | — | — |
| 312-206 | A | Chicago Zone 01-Wabash | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | BURGILAHGT3 | 358 | — | — |
| 312-207 | 0 | Chicago Zone 01-Canal | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO CANAL | 358 | — | — |
| 312-207 | 1 | Chicago Zone 01-Canal | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO CANAL | 358 | — | — |
| 312-207 | 2 | Chicago Zone 01-Canal | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO CANAL | 358 | — | — |
| 312-207 | 3 | Chicago Zone 01-Canal | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO CANAL | 358 | — | — |
| 312-207 | 4 | Chicago Zone 01-Canal | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO CANAL | 358 | — | — |
| 312-207 | 5 | Chicago Zone 01-Canal | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO CANAL | 358 | — | — |
| 312-207 | 6 | Chicago Zone 01-Canal | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO CANAL | 358 | — | — |
| 312-207 | 7 | Chicago Zone 01-Canal | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO CANAL | 358 | — | — |
| 312-207 | 8 | Chicago Zone 01-Canal | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO CANAL | 358 | — | — |
| 312-207 | 9 | Chicago Zone 01-Canal | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | BURGILAHGT3 | 358 | — | — |
| 312-207 | A | Chicago Zone 01-Canal | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO CANAL | 358 | — | — |
| 312-208 | A | Chicago Zone 01-Wabash | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | BURGILAHGT3 | 358 | — | — |
| 312-209 | 0 | Northbrook West | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 312-209 | 1 | Northbrook West | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 312-209 | 2 | Northbrook West | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 312-209 | 3 | Northbrook West | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 312-209 | 4 | Northbrook West | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 312-209 | 5 | Northbrook West | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 312-209 | 7 | Northbrook West | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 312-209 | 8 | Northbrook West | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 312-209 | 9 | Northbrook West | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 312-209 | A | Northbrook West | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 312-210 | 0 | Chicago Zone 01-Calumet | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - IL (984E) | CHCGILWBXDZ | 358 | — | — |
| 312-210 | 1 | Chicago Zone 01-Calumet | Landline or VoIP | PEERLESS NETWORK OF ILLINOIS, LLC - IL (063E) | CHICAGO | 358 | — | — |
| 312-210 | 2 | Chicago Zone 01-Calumet | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 312-210 | 3 | Chicago Zone 01-Calumet | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 312-210 | 4 | Chicago Zone 01-Calumet | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 312-210 | 5 | Chicago Zone 01-Calumet | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 312-210 | 6 | Chicago Zone 01-Calumet | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 312-210 | 7 | Chicago Zone 01-Calumet | Landline or VoIP | ONVOY, LLC (224C) | CHICAGO | 358 | — | — |
| 312-210 | 8 | Chicago Zone 01-Calumet | Landline or VoIP | ONVOY, LLC (224C) | CHICAGO | 358 | — | — |
| 312-210 | 9 | Chicago Zone 01-Calumet | Landline or VoIP | ONVOY, LLC (224C) | CHICAGO | 358 | — | — |
| 312-210 | A | Chicago Zone 01-Calumet | Landline or VoIP | PEERLESS NETWORK OF ILLINOIS, LLC - IL (063E) | CHICAGO | 358 | — | — |
| 312-212 | 0 | Chicago Zone 01-Wabash | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - IL (6115) | CHICAGO | 358 | — | — |
| 312-212 | 1 | Chicago Zone 01-Wabash | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO WABASH | 358 | — | — |
| 312-212 | 2 | Chicago Zone 01-Wabash | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO WABASH | 358 | — | — |
| 312-212 | 3 | Chicago Zone 01-Wabash | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - IL (6115) | CHICAGO | 358 | — | — |
| 312-212 | 4 | Chicago Zone 01-Wabash | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | BENSENVILLE | 358 | — | — |
| 312-212 | 5 | Chicago Zone 01-Wabash | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | BENSENVILLE | 358 | — | — |
| 312-212 | 6 | Chicago Zone 01-Wabash | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO WABASH | 358 | — | — |
| 312-212 | 7 | Chicago Zone 01-Wabash | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | BENSENVILLE | 358 | — | — |
| 312-212 | 8 | Chicago Zone 01-Wabash | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - IL (6115) | CHICAGO | 358 | — | — |
| 312-212 | 9 | Chicago Zone 01-Wabash | Landline or VoIP | RCN TELECOM SERVICES OF ILLINIOS, INC. - IL (8702) | CHCGIL24SMD | 358 | — | — |
| 312-212 | A | Chicago Zone 01-Wabash | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO WABASH | 358 | — | — |
| 312-213 | A | Chicago Zone 01-Wabash | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | BURGILAHGT3 | 358 | — | — |
| 312-214 | A | Chicago Zone 01-Franklin | Landline | ILLINOIS BELL TEL CO (9329) | CHICAGO FRANKLIN | 358 | — | — |
| 312-215 | 0 | Wheeling | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | SCBGILRRGT1 | 358 | — | — |
| 312-215 | 1 | Wheeling | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | SCBGILRRGT1 | 358 | — | — |
| 312-215 | 2 | Wheeling | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | SCBGILRRGT1 | 358 | — | — |
| 312-215 | 3 | Wheeling | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | SCBGILRRGT1 | 358 | — | — |
| 312-215 | 5 | Wheeling | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | SCBGILRRGT1 | 358 | — | — |
| 312-215 | 6 | Wheeling | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | SCBGILRRGT1 | 358 | — | — |
| 312-215 | 7 | Wheeling | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | SCBGILRRGT1 | 358 | — | — |
| 312-215 | 8 | Wheeling | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | SCBGILRRGT1 | 358 | — | — |
| 312-215 | A | Wheeling | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | SCBGILRRGT1 | 358 | — | — |
| 312-216 | 0 | Chicago Zone 01-Calumet | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - IL (984E) | CHCGILWBXDZ | 358 | — | — |
| 312-216 | 1 | Chicago Zone 01-Calumet | Landline or VoIP | FIRST COMMUNICATIONS, LLC (460K) | CHCGILWUX6X | 358 | — | — |
| 312-216 | 2 | Chicago Zone 01-Calumet | Landline or VoIP | ACCESS ONE, INC. - IL (5447) | CHCGILDTKMD | 358 | — | — |
| 312-216 | 3 | Chicago Zone 01-Calumet | Landline or VoIP | TELEPORT COMMUNICATIONS AMERICA, LLC - IL (7136) | OKBRILOAXEX | 358 | — | — |
| 312-216 | 4 | Chicago Zone 01-Calumet | Landline or VoIP | PAETEC ITEL, LLC (829J) | CHCGILWBXWZ | 358 | — | — |
| 312-216 | 5 | Chicago Zone 01-Calumet | Landline or VoIP | PAETEC ITEL, LLC (829J) | CHCGILWBXWZ | 358 | — | — |
| 312-216 | 6 | Chicago Zone 01-Calumet | Landline or VoIP | PAETEC ITEL, LLC (829J) | CHCGILWBXWZ | 358 | — | — |
| 312-216 | 7 | Chicago Zone 01-Calumet | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
Block-level assignments from the North American Numbering Plan administrator, via localcallingguide.com.
Assigned Prefixes
784
Assignment Blocks
4,666
Rate Centers
15
Carriers of Record
41
| Type | Blocks | Share |
|---|---|---|
| Landline | 1,124 | 24% |
| Landline or VoIP | 2,011 | 43% |
| Wireless | 1,531 | 33% |
| Carrier | Blocks |
|---|---|
| ILLINOIS BELL TEL CO | 1,124 |
| T-MOBILE USA, INC. | 856 |
| LEVEL 3 COMMUNICATIONS, LLC - IL | 367 |
| NEW CINGULAR WIRELESS PCS, LLC - IL | 367 |
| ONVOY, LLC | 292 |
| BANDWIDTH.COM CLEC, LLC - IL | 287 |
| CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL | 243 |
| MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 237 |
| TELEPORT COMMUNICATIONS AMERICA, LLC - IL | 164 |
| FIRST COMMUNICATIONS, LLC | 132 |
| 31 other carriers | 597 |
Carrier of record for each block. Numbers ported to another carrier keep their original block assignment, so this is not a lookup of who serves a given number today.
| Rate Center | Prefixes | Blocks |
|---|---|---|
| Chicago Zone 01-Calumet | 274 | 2,684 |
| Chicago Zone 01-Wabash | 192 | 641 |
| Chicago Zone 01-Franklin | 102 | 402 |
| Chicago Zone 01-Canal | 55 | 395 |
| Chicago Zone 01-Superior | 44 | 154 |
| Chicago Zone 01-Monroe | 33 | 143 |
| Chicago Zone 01-Illinois Dearborn | 28 | 58 |
| Chicago Zone 01-Lakeshore | 18 | 68 |
| Wheeling | 12 | 35 |
| Hinsdale | 11 | 20 |
| La Grange | 8 | 18 |
| Northbrook West | 3 | 22 |
| Schaumburg | 2 | 4 |
| Chicago Zone 04-Humboldt | 1 | 11 |
| Chicago Zone 07-Stewart | 1 | 11 |
A rate center is the telephone exchange area a number is homed to. It sets local calling boundaries, and is not the caller's current location.
Area code 312 is a North American Numbering Plan (NANP) telephone area code assigned to Illinois, United States. It is one of 17 area codes serving Illinois. As population and demand for phone numbers grew, the region was divided into multiple numbering plan areas to avoid exhausting the available 7-digit number pool.
Yes. 312 is an active North American Numbering Plan (NANP) area code, currently assigned to Illinois, United States. It is safe to answer or dial calls using this area code.
Area code 312 covers 6 cities and communities in Illinois, including Chicago, Hinsdale, La Grange, Northbrook West, Schaumburg, and 1 more localities. This is based on telephone company rate center data — the geographic areas carriers use to determine local calling boundaries and to assign numbers when a business or individual requests a phone number in a specific city.
All numbers in the 312 area code observe Central Time (IANA timezone: America/Chicago). Central Time is UTC−6 in winter (CST) and UTC−5 in summer (CDT). When placing a call to a 312 number from a different time zone, check the current local time above to avoid calling outside of business hours.
From within Illinois, dial the 7-digit local number directly if calling within the same rate center, or dial 1 + 312 + 7-digit number for long-distance calls within North America. From outside the US or Canada, dial your country's international exit code followed by 1 312 XXX XXXX. The country code for both the United States and Canada in NANP is +1.
Format 312 numbers using E.164 notation as required by RFC 3966: prefix with +1 and omit dashes and parentheses (e.g., +13125550100). This format ensures tel: links work correctly on all mobile browsers and VoIP apps. See the tel: URI formatting guide for complete examples.