312
Area code 312
Illinois, United States
National (312) 555-0123, E.164 +13125550123
How the 798 central office codes (exchanges) of area code 312 were allocated, from the North American Numbering Plan's records: to which carrier, as which line type. A 312 number is mobile, fixed line or VoIP according to its exchange, the three digits after the area code; the allocation is the original one (below).
At a glance
- Country code
- +1
- State
- IL
- Exchanges on record
- 798
- Carriers on record
- 26
- Mobile 261 (33%)
- Fixed line 468 (59%)
- VoIP 55 (7%)
- No line type on record 14 (2%)
- 798 exchanges on record
Most exchanges: AT&T 442, Verizon 95, T-Mobile 71.
Check a number
Valid fixed line or mobile number in the United States.
+1
country code
312
area code
5550123
subscriber number
| Country | United States numbering plan |
|---|---|
| Line type | Fixed line or mobile |
| Carrier the block was allocated to | No carrier on record for this prefix |
| E.164 | +13125550123 |
| International | +1 312-555-0123 |
| National | (312) 555-0123 |
| RFC 3966 | tel:+1-312-555-0123 |
Source: North American Numbering Plan Administrator (NANPA); Canadian Numbering Administrator (CNAC); National numbering plan: United States (ITU)
The example is 312-555-0123: 555-0100 to 555-0199 are set aside for fictional use in every area code.
The exchange map
One cell per exchange: blocks 312 2xx to 312 9xx; in each block the row is the tens digit, the column the units digit.
- Mobile 261
- Fixed line 468
- VoIP 55
- No line type on record 14
- Not on record 2
Formats and patterns
| E.164 | +13125550123 |
|---|---|
| International | +1 312-555-0123 |
| National | (312) 555-0123 |
| RFC 3966 (tel: URI) | tel:+1-312-555-0123 |
Any 312 number, in E.164
^\+1312[2-9]\d{6}$+1, the area code, a central office code that does not start with 0 or 1, then four digits.
Mobile exchanges (261 on record)
^\+1312(?:2(?:0[03689]|1[3578]|21|3[127]|4[1689]|5[079]|7[0-3]|8[25-79]|9[0569])|3(?:0[13-57]|1[04-8]|2[03]|3[0139]|4[0239]|5[0-2489]|6[5-79]|7[0158]|8[7-9]|9[01389])|4(?:0[0-6]|1[258]|20|3[47-9]|[47][68]|5[0-279]|68|8[013-579]|9[03578])|5(?:0[1245]|1[02-589]|2[02-4]|3[1-3689]|4[357]|50|6[0-2]|7[169]|81|9[0379])|6(?:0[78]|1[0357-9]|2[23]|3[69]|47|5[679]|68|7[178]|8[457-9]|9[19])|7(?:0[89]|1[37-9]|2[0138]|3[15]|[46][09]|58|7[1-46]|8[35])|8(?:0[124-6]|1[0368]|2[56]|3[3589]|4[148]|5[129]|6[056]|7[14]|8[258]|9[018])|9(?:0[1379]|1[489]|2[579]|3[347]|41|5[236]|6[135689]|7[258]|89|9[01]))\d{4}$Fixed line exchanges (468 on record)
^\+1312(?:2(?:0[12457]|1[246]|2[02-9]|3[03-689]|4[02-57]|5[1-68]|6\d|7[4-9]|8[01348]|9[13478])|3(?:0[02689]|19|2[124-9]|3[24-8]|4[14-7]|5[35-7]|6[0-48]|7[2-479]|8[0-6]|9[4-7])|4(?:0[7-9]|1[03679]|2[1-57-9]|3[0-356]|4[0-579]|5[3-68]|6[0-79]|7[0-24579]|8[268]|9[12469])|5(?:0[367]|1[67]|2[15-9]|3[47]|4[0-24689]|5[1-46-9]|6[3-9]|7[02-578]|8[02357-9]|9[124-6])|6(?:0[1-69]|1[246]|2[1457-9]|3[02-578]|4[0-689]|5[0-58]|6[0-69]|7[02-69]|8[13]|9[02-8])|7(?:[04][1-7]|1[024-6]|2[2679]|3[02-46-9]|5[0-69]|6[2458]|7[057]|8[0-246-9]|9[0-57-9])|8(?:0[37-9]|1[2479]|2[1-47-9]|3[1246]|[47][023569]|5[03-8]|6[1-479]|8[014679]|9[2-79])|9(?:0[24-68]|1[2357]|2[0-468]|3[0-25689]|4[2-9]|5[1457]|6[02]|7[03479]|8[013-8]|9[2-79]))\d{4}$VoIP exchanges (55 on record)
^\+1312(?:2(?:1[09]|92)|3(?:1[23]|48|76|92)|4(?:14|26|73)|5(?:0[089]|3[05]|8[46]|98)|6(?:00|2[06]|31|67|8[026])|7(?:2[45]|48|57|6[1367]|7[89]|96)|8(?:[02]0|15|[34]7|68|7[78]|83)|9(?:[014]0|6[47]|71|82|98))\d{4}$The exchange patterns follow the original allocations; a number ported since keeps its digits but not necessarily its carrier or its line type.
Carriers and their exchanges
Every carrier holding exchanges in 312, with the exchanges allocated to it (the three digits after the area code).
| Carrier | Exchanges | Mobile | Fixed line | VoIP | Exchanges held |
|---|---|---|---|---|---|
| AT&T | 442 | 82 | 359 | 1 | 201–204, 206–208, 212–215, 218, 220, 222–223, 225–231, 233–236, 239–246, 251, 255, 258–259, 263, 266–267, 269, 274, 280, 282, 286, 291, 293–294, 297, 301–304, 306–309, 314–317, 320–322, 325–326, 328–332, 335–338, 341–342, 344–347, 351–357, 360–362, 364, 366, 368–369, 372, 374, 380–386, 391, 394–397, 401–402, 406–410, 412–413, 417, 419–422, 424–425, 427, 430–433, 435–436, 439–445, 447, 450, 454–456, 458, 460–464, 466–467, 469, 472, 474–475, 479–480, 482, 491–492, 494, 496, 499, 503–504, 507, 510, 513, 516, 518, 521, 524, 526–529, 531, 534, 537, 540–544, 547, 549, 551–554, 556–560, 563, 565–570, 572–576, 578, 580–583, 587–589, 591–592, 595–596, 603, 606–609, 612–616, 618, 621–623, 627, 629–630, 632–634, 640–642, 644–645, 648–649, 651–655, 658–666, 669–670, 672, 674–675, 681, 683, 692–697, 699, 701, 703–707, 710, 712, 714–716, 723, 726–727, 729–730, 732–734, 736–739, 742–747, 749–751, 755–756, 759, 762, 764–765, 768, 770, 772, 775, 777, 781–783, 785–791, 793, 795, 797–799, 806–808, 810, 812–814, 816–817, 819, 822–823, 827–829, 831–832, 834, 836, 840–846, 849–850, 852–853, 855–857, 860–862, 864–865, 867, 869, 875–877, 879–880, 886–889, 892, 899, 902, 904–906, 908, 912–913, 915, 917, 920–923, 925–926, 928, 930–932, 935–936, 938–939, 942–947, 949, 951–954, 956–957, 960–961, 970, 972, 974, 977, 979–980, 983–984, 986–993, 995–997 |
| Verizon | 95 | 54 | 41 | 0 | 205, 209, 237, 252–254, 256–257, 260, 262, 273, 275–277, 279, 284, 288, 305, 310, 318–319, 327, 339, 343, 350, 377, 403, 405, 415–416, 438, 448, 453, 470–471, 485–486, 489, 497, 501–502, 505, 515, 517, 519–520, 525, 533, 550, 561, 577, 579, 585, 590, 594, 597, 599, 601, 604, 610, 628, 636, 639, 702, 718, 720, 728, 758, 771, 780, 792, 802–803, 805, 809, 821, 824, 833, 835, 848, 859, 873, 882, 894, 897–898, 909, 914, 919, 937, 965, 968–969, 973, 999 |
| T-Mobile | 71 | 71 | 0 | 0 | 200, 217, 221, 248, 270, 285, 287, 296, 340, 358, 371, 375, 388, 399, 404, 434, 437, 446, 451, 459, 468, 476, 478, 481, 483, 487, 493, 498, 522–523, 532, 536, 538–539, 545, 593, 617, 619, 647, 656, 671, 678, 684–685, 687, 709, 719, 721, 731, 735, 774, 776, 804, 818, 825–826, 838, 866, 871, 874, 885, 890, 907, 918, 927, 929, 933–934, 966, 975, 978 |
| Lumen | 36 | 0 | 34 | 2 | 224, 238, 261, 264, 268, 278, 281, 283, 300, 324, 373, 423, 428–429, 477, 488, 546, 548, 602, 625, 631, 635, 637–638, 646, 690, 698, 752, 754, 858, 872, 893, 895–896, 962, 998 |
| USA Mobility | 33 | 33 | 0 | 0 | 249–250, 271–272, 289–290, 295, 299, 349, 359, 365, 367, 370, 378, 387, 389, 398, 418, 484, 490, 495, 512, 562, 571, 657, 677, 688, 717, 851, 891, 901, 941, 963 |
| Sinch (Inteliquent) | 20 | 0 | 0 | 20 | 312–313, 348, 376, 392, 426, 473, 500, 586, 598, 600, 626, 680, 748, 778–779, 820, 847, 910, 964 |
| American Messaging | 14 | 14 | 0 | 0 | 232, 323, 333, 390, 393, 400, 457, 514, 689, 713, 740, 760, 839, 903 |
| Paetec Itel | 13 | 0 | 13 | 0 | 379, 465, 605, 722, 741, 863, 881, 884, 924, 948, 981, 985, 994 |
| Bandwidth.com | 12 | 0 | 0 | 12 | 219, 292, 535, 620, 724–725, 757, 767, 868, 883, 967, 971 |
| Peerless Network | 10 | 0 | 0 | 10 | 210, 508–509, 667, 686, 766, 796, 800, 878, 940 |
| Astound Broadband | 9 | 0 | 9 | 0 | 298, 363, 624, 643, 650, 753, 794, 854, 955 |
| First Communications | 9 | 0 | 9 | 0 | 216, 247, 334, 506, 564, 673, 676, 784, 870 |
| Comcast | 3 | 0 | 0 | 3 | 763, 837, 982 |
| Emergency Networks | 3 | 3 | 0 | 0 | 452, 708, 773 |
| Brightlink Communications | 2 | 1 | 0 | 1 | 682, 801 |
| Indiana Paging Network | 2 | 2 | 0 | 0 | 691, 769 |
| Access One | 1 | 0 | 1 | 0 | 265 |
| Access2Go | 1 | 0 | 0 | 1 | 530 |
| Airespring | 1 | 0 | 0 | 1 | 815 |
| CSC Wireless LLC | 1 | 1 | 0 | 0 | 668 |
| Fractel | 1 | 0 | 0 | 1 | 900 |
| Telengy LLC | 1 | 0 | 0 | 1 | 761 |
| Tpx Communications | 1 | 0 | 1 | 0 | 679 |
| Voip Street | 1 | 0 | 0 | 1 | 584 |
| Vonage | 1 | 0 | 0 | 1 | 414 |
| Wavenation | 1 | 0 | 1 | 0 | 449 |
Questions developers ask
- Where is area code 312?
- Area code 312 is in Illinois, in the United States: all 798 of its exchanges on record are there. From abroad it is dialled +1 312, then the seven-digit number.
- Is a 312 number mobile or landline?
- Either: in the North American Numbering Plan the line type belongs to the exchange (the three digits after the area code), not to the area code. Of the 798 exchanges on record in 312, 261 (33%) were allocated as mobile, 468 (59%) as fixed line, 55 (7%) as VoIP and 14 (2%) have no line type on record. A number can have been ported since, to another carrier and even to another line type.
- Which carriers have numbers in area code 312?
- 26 carriers hold exchanges in 312 on record; the most: AT&T (442), Verizon (95) and T-Mobile (71). These are the original allocations: with number portability, a number may be served by another carrier today, which only a live carrier lookup (an HLR or MNP query) can tell.
- How do I validate a 312 phone number?
- In E.164 a 312 number matches ^\+1312[2-9]\d{6}$: +1, the area code, a central office code that does not start with 0 or 1, then four digits. Written nationally it reads (312) 555-0123. The exchange patterns on this page narrow it to the exchanges allocated as mobile, fixed line or VoIP.