CallataGuidesGet a local business phone number in Clayton, CA
Clayton's area code, prefixes and carriers from NANPA records, and how to put a Clayton number in front of your customers.
- Area code
- 925
- Exchanges
- 12NANPA-assigned
- Carriers
- 8
- Population
- 10,933Census 2024 est.
What area code is Clayton, CA?
Clayton, in Contra Costa County, California, had a Census-estimated population of 10,933 in July 2024. All 12 exchanges NANPA lists for its rate center are in area code 925. Clayton is in the Pacific time zone.
According to NANPA's dialing-plan data, local calls within 925 are dialed as 1 plus ten digits and toll calls as 1 plus ten digits.
| Area code | Exchanges here | Share | In service since | Overlay with | Time zone |
|---|---|---|---|---|---|
| 925 | 12 | 100% | 1998 | none | Pacific |
Source: NANPA utilized central office code file and NPA report, dated 10/01/2026.
Phone carriers in Clayton
8 carriers hold the 12 exchanges assigned to Clayton's rate center. Pacific Bell has the most, with 3. 11 of them are pooled codes, which the holder shares with other carriers in blocks of 1,000 numbers. The table counts codes by the operating company NANPA assigned them to, not by who serves each number today.
| Carrier (NANPA operating company) | Exchanges | Share |
|---|---|---|
| Pacific Bell | 3 | 25% |
| Mcimetro Access Transmission Services LLC | 2 | 17% |
| T-mobile USA, INC. | 2 | 17% |
| Level 3 Communications, LLC - CA | 1 | 8.3% |
| Teleport Communications America, LLC - CA | 1 | 8.3% |
| U.s. Telepacific Corp. d/b/a TPX Communications | 1 | 8.3% |
| Matrix Telecom, LLC. S/i/i Tnci - CA | 1 | 8.3% |
| HD Carrier LLC | 1 | 8.3% |
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.
Local prefixes for Clayton
Each prefix below is a block of up to 10,000 numbers that NANPA assigned to Clayton's rate center (CLAYTON). The earliest assignment date recorded in the file for these codes is 2001. None were assigned in 2020 or later.
| Area code | Prefixes (NXX) |
|---|---|
| 925 | 276, 304, 524, 567, 672, 673, 690, 693, 844, 889, 914, 993 |
Source: NANPA utilized central office code file.
Rate centers and local calling in Clayton
What a caller sees as "local" is the area code plus prefix. In Clayton, those come from the CLAYTON rate center, as recorded by NANPA.
If your business already has a Clayton number, porting it to Callata is free and keeps it on your cards, listings and vehicles.
Businesses around Clayton
Clayton is part of the San Francisco-Oakland-Fremont, CA metro area, home to 4.6 million people in 2024. County Business Patterns counted 133,246 business establishments in the San Francisco, CA metro area in 2023, employing 2,417,363 people. The largest sectors by establishment count are professional, scientific, and technical services (23,140), health care and social assistance (16,920), and accommodation and food services (13,736).
| Industry | Establishments | Employees | Employees per establishment |
|---|---|---|---|
| Full-service restaurants | 5,136 | 86,434 | 16.8 |
| Limited-service restaurants | 4,140 | 59,849 | 14.5 |
| Dental offices | 3,029 | 19,225 | 6.3 |
| Offices of real estate agents and brokers | 2,990 | 10,454 | 3.5 |
| Law offices | 2,984 | 25,802 | 8.6 |
| Custom computer programming services firms | 2,959 | 58,995 | 19.9 |
| Residential remodelers | 2,924 | 14,184 | 4.9 |
| Management consulting firms | 2,756 | 16,952 | 6.2 |
Selected small-business industries (six-digit NAICS) covered by these guides. Source: Census County Business Patterns 2023.
Setting up a Clayton business line
Callata Office costs $99 per month for up to 5 people, and each additional user is $20 a month. That covers up to 3 local numbers, calling from a browser or your cell, transcribed voicemail, recorded calls with AI summaries, after-hours routing and E911 on each number.
Porting a number you already use in Clayton is free, and business texting is available once the carrier registration (10DLC) is approved; the registration carries a one-time $49 fee. Which specific numbers are open in a given area code depends on carrier inventory at the time you sign up.
AI agents are optional: an AI receptionist or scheduler can pick up when the team is busy or closed, take a message, send a text or email, or transfer the call. They draw on prepaid AI minutes ($0.25/minute), disclose that they are AI, and outbound AI calls require prior consent and are limited to 8am–9pm.
The comparison below uses 18 users, the rounded average establishment size in the San Francisco, CA metro area. At list prices checked September 28, 2026, that is $449.10 a month on Ooma Office Pro and $540.00 on RingCentral RingEX Core. Callata comes to $359.00 a month for 18 users ($99 a month with 5 users included, then $20 per additional user), below both.
| 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 Clayton, CA?
925. All exchanges NANPA lists for Clayton are in 925.
How many phone companies have exchanges in Clayton?
8, holding 12 exchanges between them, according to NANPA's 10/01/2026 file.
Can I keep my existing Clayton 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 Clayton?
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).