303
Area code 303
Colorado, United States
National (303) 555-0123, E.164 +13035550123
How the 800 central office codes (exchanges) of area code 303 were allocated, from the North American Numbering Plan's records: to which carrier, as which line type. A 303 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
- CO
- Exchanges on record
- 800
- Carriers on record
- 23
- Mobile 182 (23%)
- Fixed line 580 (73%)
- VoIP 23 (3%)
- No line type on record 15 (2%)
- 800 exchanges on record
Most exchanges: Lumen 509, Verizon 91, AT&T 63.
Check a number
Valid fixed line or mobile number in the United States.
+1
country code
303
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 | +13035550123 |
| International | +1 303-555-0123 |
| National | (303) 555-0123 |
| RFC 3966 | tel:+1-303-555-0123 |
Source: North American Numbering Plan Administrator (NANPA); Canadian Numbering Administrator (CNAC); National numbering plan: United States (ITU)
The example is 303-555-0123: 555-0100 to 555-0199 are set aside for fictional use in every area code.
The exchange map
One cell per exchange: blocks 303 2xx to 303 9xx; in each block the row is the tens digit, the column the units digit.
- Mobile 182
- Fixed line 580
- VoIP 23
- No line type on record 15
Formats and patterns
| E.164 | +13035550123 |
|---|---|
| International | +1 303-555-0123 |
| National | (303) 555-0123 |
| RFC 3966 (tel: URI) | tel:+1-303-555-0123 |
Any 303 number, in E.164
^\+1303[2-9]\d{6}$+1, the area code, a central office code that does not start with 0 or 1, then four digits.
Mobile exchanges (182 on record)
^\+1303(?:2(?:0[1346-8]|1[023]|29|30|4[01369]|5[0179]|6[36])|3(?:[02]4|1[09]|3[25]|49|5[0689]|78|92)|4(?:08|[18]9|3[457]|61|7[258]|9[01])|5(?:0[1-35-9]|1[0347-9]|2[0-358]|4[089]|5[039]|6[04]|7[09]|8[07-9]|9[14689])|6(?:0[19]|1[023689]|38|41|56|6[7-9]|8[67])|7(?:0[19]|1[078]|2[056]|4[68]|6[07]|75)|8(?:0[7-9]|1[07-9]|2[169]|3[46]|42|5[1259]|68|7[0578]|8[0-8]|9[01578])|9(?:0[1-35-9]|1[0235-9]|2[19]|[38]1|4[14679]|56|6[01]|9[045]))\d{4}$Fixed line exchanges (580 on record)
^\+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}$VoIP exchanges (23 on record)
^\+1303(?:2(?:76|84)|3(?:03|3[09]|5[13])|4(?:07|[69]8)|5(?:[136]5|29)|8(?:62|79)|9(?:4[35]|62|70|9[379]))\d{4}$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 303, with the exchanges allocated to it (the three digits after the area code).
| Carrier | Exchanges | Mobile | Fixed line | VoIP | Exchanges held |
|---|---|---|---|---|---|
| Lumen | 509 | 0 | 509 | 0 | 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 |
| Verizon | 91 | 60 | 31 | 0 | 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 |
| AT&T | 63 | 35 | 28 | 0 | 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 |
| T-Mobile | 39 | 39 | 0 | 0 | 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 |
| USA Mobility | 31 | 31 | 0 | 0 | 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 |
| Onvoy | 14 | 0 | 0 | 14 | 276, 330, 339, 351, 407, 468, 515, 529, 535, 565, 879, 962, 970, 993 |
| American Messaging | 11 | 11 | 0 | 0 | 203, 212, 259, 310, 508–510, 528, 559, 580, 767 |
| Comcast | 7 | 0 | 0 | 7 | 284, 353, 498, 862, 945, 997, 999 |
| Allstream | 3 | 0 | 3 | 0 | 577, 597, 996 |
| Bijou Telephone Cooperative Association | 2 | 0 | 2 | 0 | 769, 822 |
| Communications Unlimited | 2 | 2 | 0 | 0 | 701, 836 |
| Emergency Networks | 2 | 2 | 0 | 0 | 491, 616 |
| Cellular One | 1 | 1 | 0 | 0 | 243 |
| Eastern Slope Rural Telephone Association | 1 | 0 | 1 | 0 | 644 |
| Elbert County Wireless | 1 | 1 | 0 | 0 | 319 |
| Forthought.net | 1 | 0 | 1 | 0 | 815 |
| HD Carrier | 1 | 0 | 0 | 1 | 303 |
| Live Wire Net | 1 | 0 | 1 | 0 | 396 |
| Microtech-Tel | 1 | 0 | 1 | 0 | 867 |
| Paetec Itel | 1 | 0 | 1 | 0 | 532 |
| Roggen Telephone Cooperative Company | 1 | 0 | 1 | 0 | 849 |
| Skyetel | 1 | 0 | 0 | 1 | 943 |
| TDS Telecom | 1 | 0 | 1 | 0 | 622 |
Questions developers ask
- Where is area code 303?
- 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.
- Is a 303 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 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.
- Which carriers have numbers in area code 303?
- 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.
- How do I validate a 303 phone number?
- 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.