{ "url": "https://phonelookup.dev/prefix/us-312", "npa": "312", "slug": "us-312", "iso": "US", "country": "United States", "regions": [ { "code": "IL", "name": "Illinois", "exchanges": 798 } ], "exchanges": 798, "known": 784, "byLineType": { "fixed_line": 468, "mobile": 261, "unknown": 14, "voip": 55 }, "carriers": [ { "name": "AT&T", "exchanges": 442, "byLineType": { "fixed_line": 359, "mobile": 82, "voip": 1 }, "ranges": [ "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" ] }, { "name": "Verizon", "exchanges": 95, "byLineType": { "fixed_line": 41, "mobile": 54 }, "ranges": [ "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" ] }, { "name": "T-Mobile", "exchanges": 71, "byLineType": { "mobile": 71 }, "ranges": [ "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" ] }, { "name": "Lumen", "exchanges": 36, "byLineType": { "fixed_line": 34, "voip": 2 }, "ranges": [ "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" ] }, { "name": "USA Mobility", "exchanges": 33, "byLineType": { "mobile": 33 }, "ranges": [ "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" ] }, { "name": "Sinch (Inteliquent)", "exchanges": 20, "byLineType": { "voip": 20 }, "ranges": [ "312–313", "348", "376", "392", "426", "473", "500", "586", "598", "600", "626", "680", "748", "778–779", "820", "847", "910", "964" ] }, { "name": "American Messaging", "exchanges": 14, "byLineType": { "mobile": 14 }, "ranges": [ "232", "323", "333", "390", "393", "400", "457", "514", "689", "713", "740", "760", "839", "903" ] }, { "name": "Paetec Itel", "exchanges": 13, "byLineType": { "fixed_line": 13 }, "ranges": [ "379", "465", "605", "722", "741", "863", "881", "884", "924", "948", "981", "985", "994" ] }, { "name": "Bandwidth.com", "exchanges": 12, "byLineType": { "voip": 12 }, "ranges": [ "219", "292", "535", "620", "724–725", "757", "767", "868", "883", "967", "971" ] }, { "name": "Peerless Network", "exchanges": 10, "byLineType": { "voip": 10 }, "ranges": [ "210", "508–509", "667", "686", "766", "796", "800", "878", "940" ] }, { "name": "Astound Broadband", "exchanges": 9, "byLineType": { "fixed_line": 9 }, "ranges": [ "298", "363", "624", "643", "650", "753", "794", "854", "955" ] }, { "name": "First Communications", "exchanges": 9, "byLineType": { "fixed_line": 9 }, "ranges": [ "216", "247", "334", "506", "564", "673", "676", "784", "870" ] }, { "name": "Comcast", "exchanges": 3, "byLineType": { "voip": 3 }, "ranges": [ "763", "837", "982" ] }, { "name": "Emergency Networks", "exchanges": 3, "byLineType": { "mobile": 3 }, "ranges": [ "452", "708", "773" ] }, { "name": "Brightlink Communications", "exchanges": 2, "byLineType": { "mobile": 1, "voip": 1 }, "ranges": [ "682", "801" ] }, { "name": "Indiana Paging Network", "exchanges": 2, "byLineType": { "mobile": 2 }, "ranges": [ "691", "769" ] }, { "name": "Access One", "exchanges": 1, "byLineType": { "fixed_line": 1 }, "ranges": [ "265" ] }, { "name": "Access2Go", "exchanges": 1, "byLineType": { "voip": 1 }, "ranges": [ "530" ] }, { "name": "Airespring", "exchanges": 1, "byLineType": { "voip": 1 }, "ranges": [ "815" ] }, { "name": "CSC Wireless LLC", "exchanges": 1, "byLineType": { "mobile": 1 }, "ranges": [ "668" ] }, { "name": "Fractel", "exchanges": 1, "byLineType": { "voip": 1 }, "ranges": [ "900" ] }, { "name": "Telengy LLC", "exchanges": 1, "byLineType": { "voip": 1 }, "ranges": [ "761" ] }, { "name": "Tpx Communications", "exchanges": 1, "byLineType": { "fixed_line": 1 }, "ranges": [ "679" ] }, { "name": "Voip Street", "exchanges": 1, "byLineType": { "voip": 1 }, "ranges": [ "584" ] }, { "name": "Vonage", "exchanges": 1, "byLineType": { "voip": 1 }, "ranges": [ "414" ] }, { "name": "Wavenation", "exchanges": 1, "byLineType": { "fixed_line": 1 }, "ranges": [ "449" ] } ], "grid": "mffmffmfmmvufmfmfmmvfmfffffffffmmffffmfffmffffmfmmmffffffmfmffffffffffmmmmffffffffmffmmmfmmfvffmmffmfmfmmmfmffmuvvmmmmmfmffmffffffmmfmfffffmmfmmffffvmmmmfmfffmmfffffmmmfmmmfffmvfmffffffffmmmmmvmffffmmmmmmmmmffffumfvmffmfmfffffvfffffffmffmmmffffffmfmfmmmffffmfmffffffffmffffvffmfmfmmfmmmfmfmmffmfmfmmfvmmfmmffvvmummmmffmmmfmmmfffffvmmmfvmfmmfffmfmfmffmffffuffffmmmffffffffmffffmffmfmffvfvfffmffmfffmvmvffffffmmfmufmfmfmmmvfmmffvffffvffffmffmfffffffmffffffffmmfmfffffffvmffmfffffmmfvfvfmmvmmmfmfffffffmufffffffmmfufmfffmmmmmfmvvffmffmfffmffffmfffffffvmfffffffvmfmvfvffvvfmfmmmmfmfvvfffmfmffffffffffvfffvmmfmmmfffmufmfvmfmfvffffmmfff-ffmfmfvmmfmffmffvmffmmffffffmmffffmmfvffmffmffvvfffmvfmffmfmmffffffmfvmfmfffmfmvuffmf-fmmfffffmfmfmfffmmffmffvmffffffffufmmffmfuufmfmvmmvmmfvmffmufmfffvffffffmmmffffffvf", "patterns": { "all": "^\\+1312[2-9]\\d{6}$", "fixed_line": "^\\+1312(?:2(?:0[12457]|1[246]|2[02-9]|3[03-689]|4[02-57]|5[1-68]|6\\d|7[4-9]|8[01348]|9[13478])|3(?:0[02689]|19|2[124-9]|3[24-8]|4[14-7]|5[35-7]|6[0-48]|7[2-479]|8[0-6]|9[4-7])|4(?:0[7-9]|1[03679]|2[1-57-9]|3[0-356]|4[0-579]|5[3-68]|6[0-79]|7[0-24579]|8[268]|9[12469])|5(?:0[367]|1[67]|2[15-9]|3[47]|4[0-24689]|5[1-46-9]|6[3-9]|7[02-578]|8[02357-9]|9[124-6])|6(?:0[1-69]|1[246]|2[1457-9]|3[02-578]|4[0-689]|5[0-58]|6[0-69]|7[02-69]|8[13]|9[02-8])|7(?:[04][1-7]|1[024-6]|2[2679]|3[02-46-9]|5[0-69]|6[2458]|7[057]|8[0-246-9]|9[0-57-9])|8(?:0[37-9]|1[2479]|2[1-47-9]|3[1246]|[47][023569]|5[03-8]|6[1-479]|8[014679]|9[2-79])|9(?:0[24-68]|1[2357]|2[0-468]|3[0-25689]|4[2-9]|5[1457]|6[02]|7[03479]|8[013-8]|9[2-79]))\\d{4}$", "mobile": "^\\+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}$", "voip": "^\\+1312(?:2(?:1[09]|92)|3(?:1[23]|48|76|92)|4(?:14|26|73)|5(?:0[089]|3[05]|8[46]|98)|6(?:00|2[06]|31|67|8[026])|7(?:2[45]|48|57|6[1367]|7[89]|96)|8(?:[02]0|15|[34]7|68|7[78]|83)|9(?:[014]0|6[47]|71|82|98))\\d{4}$" }, "sandbox": { "input": "+13125550123", "valid": true, "type": "Fixed line or mobile", "region": "US", "formats": { "e164": "+13125550123", "international": "+1 312-555-0123", "national": "(312) 555-0123", "rfc3966": "tel:+1-312-555-0123" }, "parts": { "countryCode": "+1", "destinationCode": "312", "destinationKind": "area code", "subscriber": "5550123" } }, "faq": [ { "question": "Where is area code 312?", "answer": "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." }, { "question": "Is a 312 number mobile or landline?", "answer": "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." }, { "question": "Which carriers have numbers in area code 312?", "answer": "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." }, { "question": "How do I validate a 312 phone number?", "answer": "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." } ], "neighbours": { "sameRegion": [ "us-217", "us-224", "us-309", "us-331", "us-447", "us-464", "us-618", "us-630", "us-708", "us-730", "us-773", "us-779", "us-815", "us-847", "us-872" ], "previous": "us-310", "next": "us-313" }, "meta": { "dataAsOf": "2026-10-25", "dataPoints": 798, "references": [ { "authority": "NANPA", "title": "North American Numbering Plan Administrator", "url": "https://nanpa.com/" }, { "authority": "CNAC", "title": "Canadian Numbering Administrator", "url": "https://www.cnac.ca/" }, { "authority": "ITU", "title": "National numbering plan: United States", "url": "https://www.itu.int/oth/T02020000DE/en" } ] } }