CallataGuidesGet a local business phone number in St. Charles, MO
St. Charles's area code, prefixes and carriers from NANPA records, and how to put a St. Charles number in front of your customers.
- Area code
- 636
- Exchanges
- 44NANPA-assigned
- Carriers
- 14
- Population
- 72,458Census 2024 est.
St. Charles area codes
With 72,458 residents in the Census 2024 estimate, St. Charles sits in St. Charles County, Missouri. All 44 exchanges NANPA lists for its rate center are in area code 636. St. Charles is in the Central time zone.
According to NANPA's dialing-plan data, local calls within 636 are dialed as seven digits and toll calls as 1 plus ten digits.
| Area code | Exchanges here | Share | In service since | Overlay with | Time zone |
|---|---|---|---|---|---|
| 636 | 44 | 100% | 1999 | none | Central |
Source: NANPA utilized central office code file and NPA report, dated 10/01/2026.
Phone carriers in St. Charles
14 carriers hold the 44 exchanges assigned to St. Charles's rate center. Southwestern Bell has the most, with 11. 30 of them are pooled codes, which the holder shares with other carriers in blocks of 1,000 numbers. A business number in St. Charles can come from any of these blocks; once it is yours, porting lets it move between providers.
| Carrier (NANPA operating company) | Exchanges | Share |
|---|---|---|
| Southwestern Bell | 11 | 25% |
| Onvoy, LLC - Mo | 5 | 11% |
| Mcimetro Access Transmission Services LLC - Mo | 5 | 11% |
| T-mobile USA, INC. | 4 | 9.1% |
| New Cingular Wireless PCS, LLC - Il | 4 | 9.1% |
| Level 3 Communications, LLC - Mo | 4 | 9.1% |
| AT&T Enterprises, LLC | 2 | 4.5% |
| Charter Ip Enabled Services, LLC | 2 | 4.5% |
| Paetec Itel, LLC | 2 | 4.5% |
| Cellco Partnership d/b/a Verizon Wireless - Mo | 1 | 2.3% |
| Peerless Network of Missouri, LLC - Mo | 1 | 2.3% |
| Shelcomm | 1 | 2.3% |
Carrier names are the operating company (OCN) names on NANPA's utilized central office code file dated 10/01/2026. A carrier holding a code may port numbers to other carriers.
Exchanges (NPA-NXX) assigned in St. Charles
Each prefix below is a block of up to 10,000 numbers that NANPA assigned to St. Charles's rate center (ST CHARLES). The earliest assignment date recorded in the file for these codes is 2001. 2 of the 44 were assigned in 2020 or later.
| Area code | Prefixes (NXX) |
|---|---|
| 636 | 206, 219, 233, 246, 255, 260, 277, 288, 301, 328, 352, 373, 389, 395, 410, 443, 448, 487, 493, 541, 573, 574, 578, 627, 634, 669, 688, 699, 723, 724, 734, 754, 757, 773, 795, 800, 866, 896, 916, 925, 940, 946, 947, 949 |
Source: NANPA utilized central office code file.
When St. Charles's exchanges were assigned
Assignment dates show when each block of St. Charles numbers was added to the local supply.
| Decade assigned | Exchanges | Share |
|---|---|---|
| 2000s | 6 | 55% |
| 2010s | 3 | 27% |
| 2020s | 2 | 18% |
Assignment dates as recorded in NANPA's utilized code file; codes without a recorded date are excluded.
What makes a number local to St. Charles
NANPA ties every exchange to a rate center. For St. Charles that is ST CHARLES, so a number from one of these exchanges reads as local to people in and around St. Charles.
Keeping an existing St. Charles number costs nothing on Callata, because porting is free; a new number depends on what carriers have open in 636 when you pick it.
Businesses around St. Charles
St. Charles is part of the St. Louis, MO-IL metro area, home to 2.8 million people in 2024. County Business Patterns counted 69,470 business establishments in the St. Louis, MO-IL metro area in 2023, employing 1,263,674 people. The largest sectors by establishment count are health care and social assistance (10,427), retail trade (8,095), and professional, scientific, and technical services (7,057).
| Industry | Establishments | Employees | Employees per establishment |
|---|---|---|---|
| Limited-service restaurants | 2,334 | 45,289 | 19.4 |
| Full-service restaurants | 2,019 | 49,930 | 24.7 |
| Agencies providing services for the elderly and persons with disabilities | 1,898 | 16,546 | 8.7 |
| Physician practices | 1,785 | 22,126 | 12.4 |
| Insurance agencies and brokerages | 1,509 | 7,839 | 5.2 |
| Law offices | 1,393 | 10,509 | 7.5 |
| Offices of real estate agents and brokers | 1,099 | 2,523 | 2.3 |
| Landscaping services | 1,092 | 7,504 | 6.9 |
Selected small-business industries (six-digit NAICS) covered by these guides. Source: Census County Business Patterns 2023.
Business phone service in St. Charles
For $99 a month, Callata puts a team of up to 5 on one plan ($20 for each person after that): up to 3 local numbers, unlimited inbound calls, a pooled allowance of 1,500 outbound US and Canada minutes per user, browser and cell calling, voicemail transcription with urgency triage, recorded calls with AI summaries and business-hours routing, with E911 on every number.
If you already have a number in St. Charles, porting it to Callata is free. Texting from a local number requires a one-time carrier registration (10DLC, $49), and the numbers available in any area code depend on carrier inventory when you choose them.
Optional AI agents (receptionist, sales, support or scheduler) can answer calls after hours or when nobody picks up, take messages, text, email and transfer to your team. They are billed from prepaid AI minutes at $0.25 per minute, identify themselves as AI, and may only place outbound calls to people who consented, between 8am and 9pm.
An 18-person team is the benchmark here, the rounded average establishment size in the St. Louis, MO-IL metro area. Billed per seat at month-to-month list prices (checked September 28, 2026), RingCentral RingEX Core costs $540.00 a month and Ooma Office Pro $449.10. On Callata the same 18 people cost $359.00 a month, less than either per-seat plan.
| Provider (plan) | Pricing basis | Per month | Per year |
|---|---|---|---|
| Callata (Callata Office) | $99 incl. 5 users, $20 per extra user | $359.00 | $4,308.00 |
| Quo (Starter) | $19.00 per user | $342.00 | $4,104.00 |
| Nextiva (Core) | $23.00 per user | $414.00 | $4,968.00 |
| Ooma (Office Pro) | $24.95 per user | $449.10 | $5,389.20 |
| Dialpad (Standard) | $27.00 per user | $486.00 | $5,832.00 |
| RingCentral (RingEX Core) | $30.00 per user | $540.00 | $6,480.00 |
Competitor prices are each vendor's published month-to-month list price per user for its lowest plan that includes business calling and texting, checked September 28, 2026: Quo Starter $19, Nextiva Core $23, Ooma Office Pro $24.95 (Essentials excludes texting; one-time $29.95 activation not included), Dialpad Standard $27, RingCentral RingEX Core $30 ($20 billed annually). Prices exclude taxes and fees and may change; annual contracts lower some competitors' prices.
Frequently asked questions
What area code is St. Charles, MO?
636. All exchanges NANPA lists for St. Charles are in 636.
How many phone companies have exchanges in St. Charles?
14, holding 44 exchanges between them, according to NANPA's 10/01/2026 file.
Can I keep my existing St. Charles business number?
Yes. Porting an existing number to Callata is free. Texting from it starts after carrier registration (10DLC), a one-time $49 fee.
How much is a business phone line in St. Charles?
Callata is $99 a month with 5 users included, then $20 per additional user, with up to 3 local numbers; 18 users come to $359.00 a month. For comparison, 18 users on RingCentral RingEX Core list at $540.00 a month (checked September 28, 2026).