{ "url": "https://phonelookup.dev/prefix/us-831", "npa": "831", "slug": "us-831", "iso": "US", "country": "United States", "regions": [ { "code": "CA", "name": "California", "exchanges": 442 } ], "exchanges": 442, "known": 408, "byLineType": { "fixed_line": 210, "mobile": 98, "unknown": 34, "voip": 100 }, "carriers": [ { "name": "AT&T", "exchanges": 176, "byLineType": { "fixed_line": 136, "mobile": 35, "voip": 5 }, "ranges": [ "201", "205", "214", "216–219", "226", "229", "238–239", "241–242", "249", "251–252", "254", "258", "260–261", "265", "269", "284", "292", "294", "321", "326–327", "331–336", "338–339", "372–373", "375", "382", "384–386", "392–394", "402", "419–427", "429–431", "435", "438–440", "442–444", "449", "453–455", "457–462", "464–466", "469", "471", "475–477", "479", "484", "502", "521", "524", "575", "578", "582–583", "594–596", "620", "622–628", "630", "632–638", "641–649", "655–659", "661–663", "667", "673–676", "678–679", "684–685", "687–689", "710", "722", "724", "726", "728", "740", "747", "751", "753–755", "757–759", "761", "763", "766", "768–772", "775", "783–784", "786", "796", "824", "840", "883–884", "899", "905", "915", "917" ] }, { "name": "Verizon", "exchanges": 41, "byLineType": { "fixed_line": 11, "mobile": 30 }, "ranges": [ "202", "206", "208", "227", "234–236", "245–247", "256", "262", "277–278", "281", "291", "316", "319–320", "337", "340", "345", "531", "533–537", "540", "566", "588", "601", "682", "713", "718", "744", "801", "809", "818", "821", "998" ] }, { "name": "Onvoy", "exchanges": 31, "byLineType": { "voip": 31 }, "ranges": [ "204", "257", "268", "272–273", "286", "298", "318", "322", "328", "343", "353", "365", "388", "417", "480", "532", "576", "603–604", "609–610", "618", "666", "704", "777", "830", "850–851", "888", "900" ] }, { "name": "Lumen", "exchanges": 30, "byLineType": { "fixed_line": 29, "voip": 1 }, "ranges": [ "223", "225", "233", "274", "293", "296", "299", "300", "302", "305–307", "350", "359", "401", "525", "612", "621", "652", "664–665", "703", "706–707", "709", "732", "741", "778", "920–921" ] }, { "name": "T-Mobile", "exchanges": 26, "byLineType": { "mobile": 26 }, "ranges": [ "207", "210", "212", "224", "240", "266", "295", "297", "325", "346", "383", "406", "428", "500", "512", "539", "585", "750", "760", "774", "776", "785", "794", "869", "902", "970" ] }, { "name": "IP Horizon", "exchanges": 14, "byLineType": { "voip": 14 }, "ranges": [ "221", "232", "237", "250", "263", "282", "498", "508", "580", "586", "607", "653", "731", "996" ] }, { "name": "Bandwidth.com", "exchanges": 11, "byLineType": { "voip": 11 }, "ranges": [ "244", "264", "275", "285", "287", "308–309", "387", "613", "708", "856" ] }, { "name": "Tpx Communications", "exchanges": 11, "byLineType": { "fixed_line": 11 }, "ranges": [ "222", "253", "259", "267", "270", "290", "515", "574", "600", "705", "737" ] }, { "name": "Fractel", "exchanges": 10, "byLineType": { "voip": 10 }, "ranges": [ "348", "356", "432", "529", "587", "699", "788", "842", "877", "946" ] }, { "name": "Peerless Network", "exchanges": 8, "byLineType": { "voip": 8 }, "ranges": [ "200", "301", "303–304", "315", "597", "855", "999" ] }, { "name": "COMMIO LLC", "exchanges": 4, "byLineType": { "voip": 4 }, "ranges": [ "280", "283", "833", "867" ] }, { "name": "Emergency Networks", "exchanges": 4, "byLineType": { "mobile": 4 }, "ranges": [ "231", "330", "808", "931" ] }, { "name": "Spectrum", "exchanges": 4, "byLineType": { "fixed_line": 4 }, "ranges": [ "228", "288", "313", "593" ] }, { "name": "Utility Telephone", "exchanges": 4, "byLineType": { "fixed_line": 4 }, "ranges": [ "572", "756", "889", "948" ] }, { "name": "Comcast", "exchanges": 3, "byLineType": { "fixed_line": 3 }, "ranges": [ "289", "324", "975" ] }, { "name": "Pac-West Telecomm", "exchanges": 3, "byLineType": { "fixed_line": 3 }, "ranges": [ "677", "789", "854" ] }, { "name": "TELNYX", "exchanges": 3, "byLineType": { "voip": 3 }, "ranges": [ "230", "271", "276" ] }, { "name": "Ton80 Communications", "exchanges": 3, "byLineType": { "voip": 3 }, "ranges": [ "366", "837", "844" ] }, { "name": "HD Carrier", "exchanges": 2, "byLineType": { "voip": 2 }, "ranges": [ "215", "859" ] }, { "name": "Nuso", "exchanges": 2, "byLineType": { "fixed_line": 2 }, "ranges": [ "203", "886" ] }, { "name": "Pinnacles Telephone Company", "exchanges": 2, "byLineType": { "fixed_line": 2 }, "ranges": [ "389", "693" ] }, { "name": "8x8", "exchanges": 1, "byLineType": { "voip": 1 }, "ranges": [ "880" ] }, { "name": "Brightlink Communications", "exchanges": 1, "byLineType": { "voip": 1 }, "ranges": [ "329" ] }, { "name": "CSC Wireless LLC", "exchanges": 1, "byLineType": { "mobile": 1 }, "ranges": [ "243" ] }, { "name": "Dish Wireless", "exchanges": 1, "byLineType": { "mobile": 1 }, "ranges": [ "279" ] }, { "name": "Exiant", "exchanges": 1, "byLineType": { "voip": 1 }, "ranges": [ "468" ] }, { "name": "Leap Telecom", "exchanges": 1, "byLineType": { "fixed_line": 1 }, "ranges": [ "317" ] }, { "name": "North County Communications", "exchanges": 1, "byLineType": { "fixed_line": 1 }, "ranges": [ "255" ] }, { "name": "Optimum", "exchanges": 1, "byLineType": { "fixed_line": 1 }, "ranges": [ "312" ] }, { "name": "Shelltel", "exchanges": 1, "byLineType": { "mobile": 1 }, "ranges": [ "314" ] }, { "name": "Skyetel", "exchanges": 1, "byLineType": { "voip": 1 }, "ranges": [ "800" ] }, { "name": "Terra Nova Telecom", "exchanges": 1, "byLineType": { "voip": 1 }, "ranges": [ "887" ] }, { "name": "Twilio International", "exchanges": 1, "byLineType": { "voip": 1 }, "ranges": [ "717" ] }, { "name": "Voip Street", "exchanges": 1, "byLineType": { "voip": 1 }, "ranges": [ "400" ] }, { "name": "Vonage", "exchanges": 1, "byLineType": { "voip": 1 }, "ranges": [ "220" ] }, { "name": "Wavenation", "exchanges": 1, "byLineType": { "fixed_line": 1 }, "ranges": [ "901" ] }, { "name": "Wide Voice", "exchanges": 1, "byLineType": { "fixed_line": 1 }, "ranges": [ "881" ] } ], "grid": "vmffvfmmmumumumvffffvvffmvvmfmvmvfmmmvmmmffmvmmmuvvmmfmfmvmfmmmvvvmfvffvvvfvvmmmvmvvmvvvfffmmfmmfmvffvfvvfffvvuuffmvffvfmmvufmmmvvmmmfmffffmm--v-mm-v-f--v--v--f-----vv-----ff-f------fmfffvvf--fff-----vfm---m-u--u-----v-mffffffffmfffv--f--fff-fff----f---vff-ffffff-fff-vf-f---fff-fv---f-------------v-m-f-----v-uum--f-----m--mf---v-fvffffm-mm--------------u------u---m-----f-ffv-m-v-ff-mvvm----fmmmv--fm-vv--v-vvufv----vufffffffff-f-fffffff--fffffffffu-fv-fffff-fffffvf-----mffffff--m-ff-fff---f-----vu--fvfffvfmu-mu--vf---f-f-f-f--vf----f--ff--m--v--mf-fffffffmf-f--f-fffff-mfmvf----ffmf-vf----m-f---vm---u--mm-u------m--m--f---u-vu-v---v--m-v-v-----vv--fvv-uv-------v-m-------v--vf-ff-fvvf---------fvfm--m---u-u---mum--ff---------m--------------v-fuuu------uu----------m----fu-----------u-------v-fv", "patterns": { "all": "^\\+1831[2-9]\\d{6}$", "fixed_line": "^\\+1831(?:2(?:0[235]|1[6-9]|2[238]|33|4[12]|5[359]|6[79]|7[04]|8[89]|9[0369])|3(?:0[025-7]|1[23679]|24|3[35-8]|5[09]|7[235]|8[24-69]|9[2-4])|4(?:01|2[0-79]|3[01589]|4[02-49]|5[457-9]|6[0-24-69]|7[15-79]|84)|5(?:02|[12]5|3[13-6]|7[245]|8[23]|93)|6(?:00|12|2[0-8]|3[02-8]|4[1-9]|5[25-9]|6[1-57]|7[4-9]|8[457-9]|93)|7(?:0[35-79]|18|2[2468]|3[27]|4[01]|5[13-9]|6[13689]|7[0-258]|8[3469]|96)|8(?:[25]4|8[13469]|99)|9(?:01|2[01]|[49]8|75))\\d{4}$", "mobile": "^\\+1831(?:2(?:0[16-8]|1[024]|2[479]|3[14-689]|4[035-7]|5[12468]|6[0-26]|7[7-9]|8[14]|9[12457])|3(?:14|2[015-7]|3[0-249]|4[056]|83)|4(?:0[26]|19|28)|5(?:[04]0|12|2[14]|3[79]|66|78|8[58]|9[4-6])|6(?:01|73|82)|7(?:1[03]|[49]4|[56]0|7[46]|85)|8(?:0[189]|18|21|40|69)|9(?:0[25]|1[57]|31|70))\\d{4}$", "voip": "^\\+1831(?:2(?:0[04]|15|2[0156]|3[027]|4[49]|5[07]|6[3-58]|7[1-356]|8[0235-7]|98)|3(?:0[13489]|1[58]|2[289]|4[38]|5[36]|6[56]|8[78])|4(?:[08]0|17|32|53|[69]8)|5(?:08|29|32|76|8[067]|97)|6(?:0[3479]|1[038]|53|66|99)|7(?:0[48]|[147]7|31|88)|8(?:00|3[037]|4[24]|5[01569]|[67]7|8[078])|9(?:00|46|9[69]))\\d{4}$" }, "sandbox": { "input": "+18315550123", "valid": true, "type": "Fixed line or mobile", "region": "US", "formats": { "e164": "+18315550123", "international": "+1 831-555-0123", "national": "(831) 555-0123", "rfc3966": "tel:+1-831-555-0123" }, "parts": { "countryCode": "+1", "destinationCode": "831", "destinationKind": "area code", "subscriber": "5550123" } }, "faq": [ { "question": "Where is area code 831?", "answer": "Area code 831 is in California, in the United States: all 442 of its exchanges on record are there. From abroad it is dialled +1 831, then the seven-digit number." }, { "question": "Is a 831 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 442 exchanges on record in 831, 98 (22%) were allocated as mobile, 210 (48%) as fixed line, 100 (23%) as VoIP and 34 (8%) 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 831?", "answer": "37 carriers hold exchanges in 831 on record; the most: AT&T (176), Verizon (41) and Onvoy (31). 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 831 phone number?", "answer": "In E.164 a 831 number matches ^\\+1831[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 (831) 555-0123. The exchange patterns on this page narrow it to the exchanges allocated as mobile, fixed line or VoIP." } ], "neighbours": { "sameRegion": [ "us-209", "us-213", "us-279", "us-310", "us-323", "us-341", "us-350", "us-369", "us-408", "us-415", "us-424", "us-442", "us-510", "us-530", "us-559", "us-562", "us-619", "us-626", "us-628", "us-650", "us-657", "us-661", "us-669", "us-707", "us-714", "us-738", "us-747", "us-760", "us-805", "us-818", "us-820", "us-840", "us-858", "us-909", "us-916", "us-925", "us-949", "us-951" ], "previous": "us-830", "next": "us-832" }, "meta": { "dataAsOf": "2026-10-25", "dataPoints": 442, "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" } ] } }