Area Code 925
California
Area code 925 serves California, primarily Concord, in the Pacific Time (PT) time zone. It was created from a split of area code 510.
Split Area Code
This area code was created by splitting an existing area code into separate geographic regions. When a split occurs, some customers in the original area code region are assigned the new area code.
This area code was split from area code 510 (Oakland).
In service since: 14-Mar-1998
Demographics
The estimated population served by area code 925 is approximately 1,307,421. The population density is 1,672 people per square mile, which is higher than the national average of 94. The median household income is $125,727, which is higher than the national median of $78,538. Approximately 46.4% of adults hold a bachelor's degree or higher, compared to the national rate of 35.0%. This rate is higher than the national average. The poverty rate stands at 8.5%, which is lower than the national rate of 12.4%.
History
Area code 925 was created from a split of area code 510. It was introduced in 1998 as part of a geographic division to provide additional numbering resources.
Geographic Coverage
Area code 925 serves California, primarily the Concord area, in the Pacific Time (PT). It covers 41 communities. The geographic center of this area code is approximately 37.89°N, 121.96°W.
Demographics & Economics
- Total Population
- 1,307,421
- Population Density
- 1,672 people/sq miabove U.S. average (U.S.: 94 people/sq mi)
- Median Household Income
- $125,727above U.S. median (U.S.: $78,538)
- Poverty Rate
- 8.5%below U.S. average (U.S.: 12.4%)
- Unemployment Rate
- 5.7%near U.S. average (U.S.: 5.2%)
- Education Attainment
- Bachelor's Degree+46.4%above U.S. average (U.S.: 35.0%)High School or Lower23.0%
Statistics are population-weighted aggregations from Census ACS 5-year estimates.See Sources for details.
Geographic Coverage
State
CA
Major Cities
- Concord
- Antioch
- Livermore
- San Ramon
- Mountain View
- Pleasanton
- Pittsburg
- Dublin
- Walnut Creek
- Brentwood
- Oakley
- Danville
- Martinez
- Pleasant Hill
- Lafayette
- Bay Point
- Orinda
- Moraga
- Discovery Bay
- Alamo
- Clayton
- Blackhawk
- Contra Costa Centre
- Camino Tassajara
and 17 more cities
Time Zone
- Pacific Time (PT)
Current Time
County Coverage
Population-weighted county share based on aggregated ZCTA population (100% = total mapped population for area code 925).
| County | Population | Share |
|---|---|---|
| Contra Costa, CA | 974,061 | 74.5% |
| Alameda, CA | 268,434 | 20.5% |
| Santa Clara, CA | 49,610 | 3.8% |
| San Joaquin, CA | 15,316 | 1.2% |
Call Context
This area code covers multiple cities and communities across a broad region in California. It was created as a geographic split from area code 510, dividing the original territory into separate numbering regions.
Nearby Area Codes
Area codes geographically closest to 925.
Other Area Codes in California
Area codes that also serve California, linked for easy comparison.
Frequently Asked Questions
Common questions about area code 925 and how phone numbering works.
Phone numbers are assigned based on where the number was originally provisioned, not the caller's current location. Mobile phones retain their number when users move, and businesses may use numbers from regions where they don't have a physical presence. VoIP services can also provision numbers from virtually any area code.
Yes, mobile phones can have numbers from any area code in the region they were activated. Wireless carriers assign numbers from available pools regardless of phone type. When users change carriers or move to new areas, they typically keep their original number, which may have a different area code than their current location.
Start by looking up the area code on this site to understand its general geographic region. For the specific number, options include using your carrier's caller ID features or checking public directories. If you suspect fraud, you can report it to the FTC. To file a complaint about robocalls or spoofed numbers, visit the FCC Consumer Complaint Center. You can also register your number with the National Do Not Call Registry to reduce unwanted calls. Keep in mind that caller ID can display any name the caller chooses to set.
Area codes are sometimes "split" when an existing code runs out of available number combinations. In a split, the original territory is divided geographically, with each portion receiving its own area code. This area code was split from area code 510. See our guide on splits and overlays for details.
While Concord is a prominent city in this area code's coverage, the code serves the broader surrounding region as well. Area codes are assigned geographically and typically cover multiple cities, towns, and communities beyond any single anchor city.
This area code covers a metropolitan region with high population density. Dense urban areas typically have higher call volumes and may have multiple overlapping area codes to meet demand for phone numbers. Businesses and residents in these areas are more likely to need additional numbering resources.