{ "url": "https://phonelookup.dev/prefix/us-303", "npa": "303", "slug": "us-303", "iso": "US", "country": "United States", "regions": [ { "code": "CO", "name": "Colorado", "exchanges": 800 } ], "exchanges": 800, "known": 785, "byLineType": { "fixed_line": 580, "mobile": 182, "unknown": 15, "voip": 23 }, "carriers": [ { "name": "Lumen", "exchanges": 509, "byLineType": { "fixed_line": 509 }, "ranges": [ "202", "205", "215–216", "220–221", "223–228", "231–239", "244–245", "247", "252", "254–255", "258", "260–261", "265", "267–275", "277–283", "285–299", "300–301", "306–309", "312–318", "320–322", "325–327", "329", "331", "333", "336–338", "340–348", "352", "355", "360–361", "363–373", "375–377", "380–389", "391", "393–395", "397–399", "400–406", "409–410", "412–418", "420–433", "436", "438–460", "462–467", "469–471", "473", "477", "480", "482–483", "485–488", "492–494", "497", "499", "500", "504", "512", "516", "526–527", "530", "533–534", "536", "538", "541", "543–547", "552", "554", "556–558", "561–563", "567", "569", "571–576", "578", "581–582", "584–586", "590", "592", "595", "602–608", "614–615", "617", "620–621", "623–631", "633–637", "639–640", "642–643", "645–655", "657–666", "670–685", "688–699", "702–703", "705–708", "712–716", "719", "721–722", "724", "727", "730–735", "737–745", "747", "750–759", "761–766", "768", "770–774", "776–784", "786–799", "800", "802–806", "812–814", "816", "820", "823", "825", "827–828", "830–833", "835", "837–841", "843–844", "846–848", "850", "853–854", "856–858", "860–861", "863–866", "869", "871–874", "889", "892–894", "896", "899", "900", "904", "914", "920", "922–926", "930", "932–940", "948", "951–955", "957", "963–967", "969", "971–975", "977–980", "982", "984–989", "992", "998" ] }, { "name": "Verizon", "exchanges": 91, "byLineType": { "fixed_line": 31, "mobile": 60 }, "ranges": [ "204", "209", "214", "217–219", "222", "229", "241–242", "263", "302", "305", "323", "328", "334–335", "349", "357–358", "390", "392", "476", "481", "489", "495–496", "501–503", "514", "518–519", "531", "539", "542", "548–551", "566", "579", "594", "656", "704", "709–710", "718", "720", "726", "729", "746", "775", "785", "801", "817–819", "829", "834", "842", "859", "868", "870", "876–877", "880", "895", "902–903", "905–910", "912–913", "915–919", "921", "928–929", "941", "947", "968", "981", "991" ] }, { "name": "AT&T", "exchanges": 63, "byLineType": { "fixed_line": 28, "mobile": 35 }, "ranges": [ "200", "248–250", "253", "256", "262", "264", "304", "324", "350", "354", "362", "374", "378–379", "408", "474–475", "478–479", "484", "506", "513", "517", "524", "537", "568", "570", "583", "588–589", "593", "600–601", "618–619", "632", "638", "717", "723", "728", "736", "748–749", "807–810", "824", "845", "881–888", "898", "927", "942", "956" ] }, { "name": "T-Mobile", "exchanges": 39, "byLineType": { "mobile": 39 }, "ranges": [ "210", "246", "257", "332", "356", "359", "419", "434–435", "437", "472", "505", "507", "520–523", "525", "564", "587", "591", "596", "598", "641", "667–669", "725", "875", "901", "931", "944", "946", "949", "960–961", "990", "994–995" ] }, { "name": "USA Mobility", "exchanges": 31, "byLineType": { "mobile": 31 }, "ranges": [ "201", "206–208", "213", "230", "240", "251", "266", "461", "490", "540", "553", "560", "599", "609–610", "612–613", "686–687", "760", "821", "826", "851–852", "855", "878", "890–891", "897" ] }, { "name": "Onvoy", "exchanges": 14, "byLineType": { "voip": 14 }, "ranges": [ "276", "330", "339", "351", "407", "468", "515", "529", "535", "565", "879", "962", "970", "993" ] }, { "name": "American Messaging", "exchanges": 11, "byLineType": { "mobile": 11 }, "ranges": [ "203", "212", "259", "310", "508–510", "528", "559", "580", "767" ] }, { "name": "Comcast", "exchanges": 7, "byLineType": { "voip": 7 }, "ranges": [ "284", "353", "498", "862", "945", "997", "999" ] }, { "name": "Allstream", "exchanges": 3, "byLineType": { "fixed_line": 3 }, "ranges": [ "577", "597", "996" ] }, { "name": "Bijou Telephone Cooperative Association", "exchanges": 2, "byLineType": { "fixed_line": 2 }, "ranges": [ "769", "822" ] }, { "name": "Communications Unlimited", "exchanges": 2, "byLineType": { "mobile": 2 }, "ranges": [ "701", "836" ] }, { "name": "Emergency Networks", "exchanges": 2, "byLineType": { "mobile": 2 }, "ranges": [ "491", "616" ] }, { "name": "Cellular One", "exchanges": 1, "byLineType": { "mobile": 1 }, "ranges": [ "243" ] }, { "name": "Eastern Slope Rural Telephone Association", "exchanges": 1, "byLineType": { "fixed_line": 1 }, "ranges": [ "644" ] }, { "name": "Elbert County Wireless", "exchanges": 1, "byLineType": { "mobile": 1 }, "ranges": [ "319" ] }, { "name": "Forthought.net", "exchanges": 1, "byLineType": { "fixed_line": 1 }, "ranges": [ "815" ] }, { "name": "HD Carrier", "exchanges": 1, "byLineType": { "voip": 1 }, "ranges": [ "303" ] }, { "name": "Live Wire Net", "exchanges": 1, "byLineType": { "fixed_line": 1 }, "ranges": [ "396" ] }, { "name": "Microtech-Tel", "exchanges": 1, "byLineType": { "fixed_line": 1 }, "ranges": [ "867" ] }, { "name": "Paetec Itel", "exchanges": 1, "byLineType": { "fixed_line": 1 }, "ranges": [ "532" ] }, { "name": "Roggen Telephone Cooperative Company", "exchanges": 1, "byLineType": { "fixed_line": 1 }, "ranges": [ "849" ] }, { "name": "Skyetel", "exchanges": 1, "byLineType": { "voip": 1 }, "ranges": [ "943" ] }, { "name": "TDS Telecom", "exchanges": 1, "byLineType": { "fixed_line": 1 }, "ranges": [ "622" ] } ], "grid": "fmfmmfmmmfmummfffffffffffffffmmfffffffffmmfmffmffmmmfffffmfmfffmffmfffffffffvfffffffvffffffffffffffffffvmfffffmufffffffmffffmfffffvfmffmfffvfffffffffmmvfvffmfmmffffffffffffffffffmfffffffffffffmffffffffffffffvmffufffffffmffffffffffffffmmfmfffffffffffffffffffffffmffffffvfffmffmffmffffffffffmmmffffffvffmmmfmmmmmmufmmvfmmmmmmmfmffmvfffffvffffmfffffffmmmffmfufffmmfffmvffffmffffffffmmffffffmmmfmffmfmfmmfmfffffffmmummffmfmmffffffffffffffffffmffmffffffffffffffmffffffffffmmmffffffffffffffffmmffffffffffffumfffffffmmufffffmmfmffffmmfffffffffffffffffffmfmfffffffffffmffffffmfffffffmfffffffffffffffffffffffffffffffmmmmufffffmmmfmffffmffmffffmfmfffffmffffffffmmffmfffmffvfffffmfmffffmfmmvmmmmmmmmmfmmfffmfmmffmmmfmmmmmmummfmmmmmfmfffffffmfmfffffffffmfvmvmmfmufffffmfuummvfffffffvfffffuffffmfuffffffmffvmmfvfv", "patterns": { "all": "^\\+1303[2-9]\\d{6}$", "fixed_line": "^\\+1303(?:2(?:0[0259]|1[4-9]|2[0-8]|3[1-9]|4[24578]|5[2-68]|6[0-2457-9]|7[0-57-9]|8[0-35-9]|9\\d)|3(?:0[0-25-9]|1[2-8]|2[0-35-9]|3[1346-8]|4[0-8]|5[2457]|[68]\\d|7[0-79]|9[013-9])|4(?:0[0-69]|1[02-8]|[245]\\d|3[0-3689]|6[02-79]|7[0134679]|8[0-8]|9[2-79])|5(?:0[04]|1[26]|2[467]|3[0-46-9]|4[1-7]|5[1246-8]|6[1-36-9]|7[1-8]|8[1-6]|9[02357])|6(?:0[02-8]|1[457]|[279]\\d|3[0-79]|4[02-9]|5[0-57-9]|6[0-6]|8[0-589])|7(?:0[2-8]|1[2-69]|2[1-47-9]|[3589]\\d|4[0-579]|6[1-689]|7[0-46-9])|8(?:0[0-6]|1[2-6]|2[02-578]|3[0-357-9]|4[013-9]|5[0346-8]|6[013-79]|7[1-46]|89|9[2-469])|9(?:0[04]|14|2[02-8]|3[02-9]|4[028]|5[1-57]|6[3-9]|7[1-57-9]|8[024-9]|9[1268]))\\d{4}$", "mobile": "^\\+1303(?:2(?:0[1346-8]|1[023]|29|30|4[01369]|5[0179]|6[36])|3(?:[02]4|1[09]|3[25]|49|5[0689]|78|92)|4(?:08|[18]9|3[457]|61|7[258]|9[01])|5(?:0[1-35-9]|1[0347-9]|2[0-358]|4[089]|5[039]|6[04]|7[09]|8[07-9]|9[14689])|6(?:0[19]|1[023689]|38|41|56|6[7-9]|8[67])|7(?:0[19]|1[078]|2[056]|4[68]|6[07]|75)|8(?:0[7-9]|1[07-9]|2[169]|3[46]|42|5[1259]|68|7[0578]|8[0-8]|9[01578])|9(?:0[1-35-9]|1[0235-9]|2[19]|[38]1|4[14679]|56|6[01]|9[045]))\\d{4}$", "voip": "^\\+1303(?:2(?:76|84)|3(?:03|3[09]|5[13])|4(?:07|[69]8)|5(?:[136]5|29)|8(?:62|79)|9(?:4[35]|62|70|9[379]))\\d{4}$" }, "sandbox": { "input": "+13035550123", "valid": true, "type": "Fixed line or mobile", "region": "US", "formats": { "e164": "+13035550123", "international": "+1 303-555-0123", "national": "(303) 555-0123", "rfc3966": "tel:+1-303-555-0123" }, "parts": { "countryCode": "+1", "destinationCode": "303", "destinationKind": "area code", "subscriber": "5550123" } }, "faq": [ { "question": "Where is area code 303?", "answer": "Area code 303 is in Colorado, in the United States: all 800 of its exchanges on record are there. From abroad it is dialled +1 303, then the seven-digit number." }, { "question": "Is a 303 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 800 exchanges on record in 303, 182 (23%) were allocated as mobile, 580 (73%) as fixed line, 23 (3%) as VoIP and 15 (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 303?", "answer": "23 carriers hold exchanges in 303 on record; the most: Lumen (509), Verizon (91) and AT&T (63). 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 303 phone number?", "answer": "In E.164 a 303 number matches ^\\+1303[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 (303) 555-0123. The exchange patterns on this page narrow it to the exchanges allocated as mobile, fixed line or VoIP." } ], "neighbours": { "sameRegion": [ "us-719", "us-720", "us-970", "us-983" ], "previous": "us-302", "next": "us-304" }, "meta": { "dataAsOf": "2026-10-25", "dataPoints": 800, "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" } ] } }