557
Area code 557
Missouri, United States
National (557) 555-0123, E.164 +15575550123
How the 97 central office codes (exchanges) of area code 557 were allocated, from the North American Numbering Plan's records: to which carrier, as which line type. A 557 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
- MO
- Exchanges on record
- 97
- Carriers on record
- 17
- Mobile 38 (39%)
- Fixed line 22 (23%)
- VoIP 23 (24%)
- No line type on record 14 (14%)
- 97 exchanges on record
Most exchanges: AT&T 38, Onvoy 18, Verizon 8.
Check a number
Valid fixed line or mobile number in the United States.
| 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 | +15575550123 |
| International | +1 557-555-0123 |
| National | (557) 555-0123 |
| RFC 3966 | tel:+1-557-555-0123 |
Source: North American Numbering Plan Administrator (NANPA); Canadian Numbering Administrator (CNAC); National numbering plan: United States (ITU)
The example is 557-555-0123: 555-0100 to 555-0199 are set aside for fictional use in every area code.
The exchange map
One cell per exchange: blocks 557 2xx to 557 9xx; in each block the row is the tens digit, the column the units digit.
- Mobile 38
- Fixed line 22
- VoIP 23
- No line type on record 14
- Not on record 703
Formats and patterns
| E.164 | +15575550123 |
|---|---|
| International | +1 557-555-0123 |
| National | (557) 555-0123 |
| RFC 3966 (tel: URI) | tel:+1-557-555-0123 |
Any 557 number, in E.164
^\+1557[2-9]\d{6}$+1, the area code, a central office code that does not start with 0 or 1, then four digits.
Mobile exchanges (38 on record)
^\+1557(?:2(?:03|1[02-47-9]|2[0357-9]|3[02-9]|4[347]|5[1-4]|6[0-4])|5(?:0[07]|67))\d{4}$Fixed line exchanges (22 on record)
^\+1557(?:2(?:0[14-7]|16|2[24]|31|4[0568]|50|73)|362|454|653|747|9(?:53|9[69]))\d{4}$VoIP exchanges (23 on record)
^\+1557(?:2(?:0[0289]|[16]5|2[16]|4[129]|5[5-9])|333|4(?:44|67)|557|777|88[08])\d{4}$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 557, with the exchanges allocated to it (the three digits after the area code).
| Carrier | Exchanges | Mobile | Fixed line | VoIP | Exchanges held |
|---|---|---|---|---|---|
| AT&T | 38 | 23 | 15 | 0 | 201, 205–206, 213–214, 216–218, 220, 224–225, 227, 229–231, 234–235, 237–238, 240, 243–245, 247, 251, 253–254, 261–264, 273, 362, 454, 653, 747, 953, 996 |
| Onvoy | 18 | 0 | 0 | 18 | 200, 208–209, 221, 226, 241–242, 249, 255–259, 265, 333, 444, 467, 557 |
| Verizon | 8 | 8 | 0 | 0 | 210, 219, 223, 228, 232, 236, 239, 260 |
| Emergency Networks | 3 | 3 | 0 | 0 | 500, 507, 567 |
| Five9 | 2 | 0 | 2 | 0 | 204, 207 |
| T-Mobile | 2 | 2 | 0 | 0 | 203, 212 |
| Terra Nova Telecom | 2 | 0 | 0 | 2 | 777, 888 |
| 8x8 | 1 | 0 | 0 | 1 | 880 |
| Callworks Corporation | 1 | 0 | 0 | 1 | 215 |
| Comcast | 1 | 0 | 0 | 1 | 202 |
| Dish Wireless | 1 | 1 | 0 | 0 | 233 |
| E. Ritter Communications | 1 | 0 | 1 | 0 | 248 |
| Leap Telecom | 1 | 0 | 1 | 0 | 222 |
| Shelltel | 1 | 1 | 0 | 0 | 252 |
| Tpx Communications | 1 | 0 | 1 | 0 | 250 |
| Wavenation | 1 | 0 | 1 | 0 | 246 |
| Wiretap Telecom | 1 | 0 | 1 | 0 | 999 |
Questions developers ask
- Where is area code 557?
- Area code 557 is in Missouri, in the United States: all 97 of its exchanges on record are there. From abroad it is dialled +1 557, then the seven-digit number.
- Is a 557 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 97 exchanges on record in 557, 38 (39%) were allocated as mobile, 22 (23%) as fixed line, 23 (24%) as VoIP and 14 (14%) 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 557?
- 17 carriers hold exchanges in 557 on record; the most: AT&T (38), Onvoy (18) and Verizon (8). 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 557 phone number?
- In E.164 a 557 number matches ^\+1557[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 (557) 555-0123. The exchange patterns on this page narrow it to the exchanges allocated as mobile, fixed line or VoIP.