Area Code 408
California
Area code 408 serves California, primarily San Jose, in the Pacific Time (PT) time zone. It has served the region since 01-Jan-1959.
Published: Last reviewed: Verified against NANPA and FCC records
Overlay Area Code
This area code shares its geographic footprint with an overlay code, so the same cities are served by two area codes. Because overlays leave existing numbers untouched, this region's relief planning favors adding codes over redrawing boundaries.
The codes serving this same region: area code 669 (San Jose).
With prefix utilization already at 98.4%, numbering resources here are under sustained pressure — context that explains why overlays were introduced.
In service since: 01-Jan-1959
Area Code Splits
One area code has been carved out of this code's original territory through a geographic split. Each split was a relief action: as demand grew, part of the region was reassigned to a new code rather than overlaying the whole territory.
Split into: area code 831 (Salinas).
Demographics & Economics
- Total Population
- 1,705,544
- Population Density
- 1,461 people/sq miabove U.S. average (U.S.: 95 people/sq mi)
- Median Household Income
- $164,281above U.S. median (U.S.: $80,734)
- Poverty Rate
- 7.1%below U.S. average (U.S.: 12.5%)
- Unemployment Rate
- 4.9%near U.S. average (U.S.: 5.2%)
- Education Attainment
- Bachelor's Degree+56.4%above U.S. average (U.S.: 35.7%)High School or Lower19.7%
Statistics are population-weighted aggregations from Census ACS 5-year estimates. Population figures are approximate — see Sources & Methodology for details on how area code populations are derived.
See how this area code compares to all US area codes in the income ranking and density ranking.
Time Zone
- Pacific Time (PT)
NANPA Relief Status
According to the latest NANPA analysis (July 2026), this area code is not currently listed as exhausting within the next 36 months. No relief planning is in progress for this NPA.
Source: NANPA NPA Relief Planning Reports · See all relief planning statuses
Current Time
Prefix Utilization
Geographic Coverage
State
CA
Major Cities
- San Jose
- Sunnyvale
- Santa Clara
- Burbank
- Milpitas
- Cupertino
- Gilroy
- Morgan Hill
- Campbell
- Los Gatos
- Saratoga
- Alum Rock
- East Foothills
- San Martin
- Cambrian Park
- Monte Sereno
- Lexington Hills
- Fruitdale
Historical Timeline of Area Code 408
On March 1, 1959, area code 408 was carved out of area code 415 to serve the rapidly expanding San Jose and South Bay region of California. The code's trajectory mirrors the rise of Silicon Valley from agricultural orchards to the world's technology capital. Source: CPUC
Key milestones:
- 1947: The region was included in area code 415, one of California's original three area codes established under the North American Numbering Plan
- 1959: Area code 408 was created on March 1 by splitting from 415 to accommodate growth in the San Jose metropolitan area Source: NANPA
- 1998: Area code 831 was split off for Santa Cruz, Salinas, Monterey, and Hollister regions
- 1998: The California Public Utilities Commission approved an overlay for the 408 region under Decision D.98-11-065
- 1999: The overlay was suspended under Decision D.99-12-051 after number conservation measures reduced the immediate need for additional assignments
- 2001: Thousand-block number pooling was implemented, extending prefix availability by over a decade
- 2011: The CPUC re-approved the overlay under Decision D.11-10-031, citing NRUF data showing imminent exhaustion
- 2012: Area code 669 was activated on November 20, becoming the first overlay in the San Francisco Bay Area
The 14-year gap between the initial overlay approval in 1998 and its activation in 2012 demonstrates the effectiveness of number conservation strategies. Thousand-block pooling, implemented in 2001, delayed exhaustion by over a decade and became a model for resource management across the numbering plan. Source: CPUC Press Release
Regulatory History
Area code 408 has been managed through California Public Utilities Commission proceedings since 1959. The regulatory record shows how number conservation measures extended the life of the original assignment by more than a decade before an overlay became necessary. Source: CPUC
| Year | Event | Docket | Regulatory Action & Impact |
|---|---|---|---|
| 1959 | Area code creation | NANPA | 408 split from area code 415 to serve the San Jose and South Bay region Source: NANPA |
| 1998 | Area code split | CPUC | Area code 831 created to serve the coastal communities of Santa Cruz, Salinas, Monterey, and Hollister |
| 1998 | Overlay approval | D.98-11-065 | CPUC approved an overlay for the 408 region to address number exhaustion Source: CPUC |
| 1999 | Overlay suspension | D.99-12-051 | CPUC suspended the overlay after number conservation measures, including thousand-block number pooling, reduced immediate need for additional numbers |
| 2001 | Number pooling | CPUC | Thousand-block number pooling implemented in the 408 area, extending prefix availability by over a decade Source: CPUC |
| 2011 | Overlay re-approval | D.11-10-031 | CPUC re-approved the overlay citing NRUF data showing imminent exhaustion Source: CPUC Decision D11-10-031 |
| 2012 | Overlay activation | CPUC | Area code 669 went into service on November 20, marking the Bay Area's first overlay Source: CPUC Press Release |
County Coverage
Population-weighted county share based on aggregated ZCTA population (100% = total mapped population for area code 408).
| County | Population | Share |
|---|---|---|
| Santa Clara, CA | 1,695,660 | 99.4% |
| Santa Cruz, CA | 9,884 | 0.6% |
Area Code 408 Family Tree
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Area code 408 was originally assigned in 01-Jan-1959 to serve CA. Over the years, it has generated 2 descendant area codes through a combination of geographic splits and overlays as demand for telephone numbers grew.
Call Context
This area code serves a major metropolitan region with high population density in CA. The primary city is San Jose.
Nearby Area Codes
Area codes geographically closest to 408.
Other Area Codes in California
Area codes that also serve California, linked for easy comparison.