Every ZIP code in the United States, with weather, radar, trivia and the numbers behind it. Five digits since 1963!

ZIP stands for Zone Improvement Plan. The codes went live on July 1, 1963.The lowest ZIP code is 00501 — the IRS in Holtsville, New York.The highest ZIP code is 99950, in Ketchikan, Alaska.Type 07734 into a calculator and turn it upside down: hELLO. It is Keansburg, New Jersey.12345 belongs to one company: General Electric in Schenectady, New York.The first digit is a region: 0 is New England and New Jersey, 9 is the West Coast, Alaska and Hawaii.Mr. ZIP, the cartoon mailman, was the mascot that sold the idea to America.ZIP+4 arrived in 1983 and can narrow a ZIP down to one side of one block.A ZIP code is a mail route, not a place: plenty of them cross county and even state lines.Play ZIP Hunt: guess the secret ZIP code of the day in six tries.
zipcodes.pro — AREA-CODE/925

925 area code

Area code 925 is in California. It covers Concord, Antioch, San Ramon and 32 other places: 36 ZIP codes in Contra Costa and Alameda counties. Local time there is , Pacific Time. In service since 1998, with no overlay.

Time zone
Pacific
Largest city
Concord
Overlays
none
In service since
1998
Rate centres
17
Prefixes assigned
640 (6,400,000 numbers)

Who calls from a 925 number

NANPA records the carrier each block of 925 numbers is assigned to. Of the 6.3 million 925 numbers assigned, 38% are with cable, internet-calling, business and other carriers (Onvoy and Level 3); 31% with mobile carriers (T-Mobile, AT&T Mobility and Verizon Wireless); 29% with local phone companies (AT&T); 2% with paging companies.

That is who the numbers were assigned to: people keep their number when they change carrier, so any one number may have moved since.

Carriers holding the most 925 numbers
CarrierKindShare
AT&TLandline29%
T-MobileMobile12%
OnvoyCable, VoIP, other11%
AT&T MobilityMobile11%
Verizon WirelessMobile8%
Level 3Cable, VoIP, other5%

An area code says where a number was issued, not where the caller is: people keep their numbers when they move, and caller ID can be set to show any number, which the FCC calls spoofing. If a call you did not expect asks for money or personal details, the FCC advises hanging up and calling the company back on a number you look up yourself. Unwanted calls can be reported to the FTC at ReportFraud.ftc.gov.

Places in area code 925

The 13 places with a telephone rate centre of their own using 925, largest first. Each links to its ZIP codes.

Places in area code 925
PlaceZIP codesPopulation
Concord, CA 8 124,035
Antioch, CA 2 116,477
Livermore, CA 2 85,522
Pleasanton, CA 2 76,960
Pittsburg, CA 1 76,257
Walnut Creek, CA 4 70,088
Danville, CA 2 43,401
Martinez, CA 1 36,903
Lafayette, CA 1 25,285
Orinda, CA 1 19,514
Moraga, CA 3 16,769
Clayton, CA 1 10,937
Sunol, CA 1 847

Nearby places using 925

These places have no rate centre of their own in NANPA's records; the nearest one uses 925. Near an area-code boundary that can be wrong for part of a town.

ZIP codes in area code 925

36 ZIP codes in 19 towns, by the town each is mailed to, largest first. Each links to its own page.

Where 925 numbers are issued

NANPA's rate centres with the most 925 prefixes (each prefix is 10,000 numbers), under NANPA's own abbreviated names.

Rate centres using area code 925
Rate centrePlacePrefixes
WALNUT CRK Walnut Creek 103
CONCORD Concord 89
PLEASANTON Pleasanton 76
ANTIOCH Antioch 67
LIVERMORE Livermore 50
BSHP RNCH — 43

Counties

The counties of its ZIP codes, most residents first, with how many of its ZIP codes each has.

Which code covers where you are now? What area code am I in? answers from your location.

Questions about area code 925

Where is area code 925?

Area code 925 is in California. It covers Concord, Antioch, San Ramon and 32 other places: 36 ZIP codes in Contra Costa and Alameda counties.

What ZIP codes are in area code 925?

36 ZIP codes, by the town each is mailed to: Concord (8, 94518 to 94529), Antioch (2, 94509 to 94531), San Ramon (2, 94582 to 94583), Livermore (2, 94550 to 94551) and 15 more towns. The full list is on this page.

What time zone is area code 925 in?

Pacific time.

Is a 925 number a mobile or a landline?

It can be either. 31% of 925 numbers are assigned to mobile carriers and 29% to local phone companies (NANPA, 2026-10-10); the rest are with cable, internet-calling, business and paging carriers. A number keeps its area code when it moves to another carrier.

Does a 925 number mean the caller is in California?

Not necessarily. An area code says where the number was first issued. People keep their numbers when they move or switch carriers, and calling software can show any number, so a 925 call can come from anywhere.

Other area codes in California

All 41 California area codes, by area, with the cities each covers

Source: NANPA NPA database, central office code and thousands-block assignments, 2026-10-10. Places are matched to NANPA's rate centres by name; see sources.

Cite this page

zipcodes.pro. “Area code 925.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/area-code/925

Underlying data is public domain or openly licensed — sources, vintages and licences.