The 650 area code covers Palo Alto, San Mateo and 10 more places in California.
Area code 650 is in California, on Pacific Time. In the 650 area, phone numbers are given out most in San Mateo County, then Santa Clara County and the City and County of San Francisco. It has been in service since August 2, 1997.
- Where
- San Mateo County, Santa Clara County and City and County of San Francisco, California
- Time zone
- Pacific Time
- In service since
- August 2, 1997
- Shares its area with
- No other area code
- Prefixes in use
- 716
- How to dial
- Local calls need 1, then the area code, then the number: 1-650-555-0142.
Find out who called you from a 650 number.
Enter the full 10-digit number to see who it is listed to and the city and state on the listing. It is the same free check as our who called me lookup. To see only the caller ID name on the number, use our free CNAM lookup. To see whether it is a mobile, a landline or a VoIP line, use our free VoIP checker. To see which carrier a (650) number is on today, use our free carrier lookup.
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Palo Alto holds 20% of the phone prefixes in area code 650.
A prefix is the three digits after the area code, and NANPA assigns each one to a town. Counting the 716 prefixes in use shows where 650 numbers are actually given out.
- Palo Alto145 prefixes, 20%
- San Mateo126 prefixes, 18%
- South San Francisco89 prefixes, 12%
- Redwood City65 prefixes, 9%
- Los Altos28 prefixes, 4%
- Millbrae24 prefixes, 3%
- San Francisco22 prefixes, 3%
- Half Moon Bay21 prefixes, 3%
Also served: Pacifica, Pescadero, La Honda and Moss Beach.
Pacific Bell (AT&T) holds the most phone number prefixes in area code 650: 272 of 716.
NANPA, which runs the North American numbering plan, assigns each prefix (the three digits after the area code) to one carrier. Here is how the 716 prefixes in use in 650 divide between carriers; holders this page does not name are grouped as other carriers.
| Carrier | Prefixes | Share |
|---|---|---|
| Pacific Bell (AT&T)AT&T's landline company | 272 | 38% |
| AT&T MobilityMobile network | 59 | 8% |
| T-MobileMobile network | 57 | 8% |
| Level 3 (Lumen)Lumen's business and wholesale network | 51 | 7% |
| Teleport (AT&T)AT&T's business phone network | 26 | 4% |
| TPX Communications | 24 | 3% |
| 26 other carriers | 227 | 32% |
72% of these prefixes are pooled, which means the blocks of 1,000 numbers inside them can belong to other carriers. Any number can also have been moved to another carrier since, so this shows who holds the prefixes, not who serves a given number.
Want the carrier of one exact number? Our free carrier lookup checks it, because numbers move between carriers.
Source: NANPA central office code assignments, October 1, 2026.
650 has covered the same ground since 1997.
1997
650 starts on August 2, 1997, split off from 415.
A 650 number on your screen can still be a scam, because caller ID is easy to fake.
- Let an unknown call go to voicemail. A real caller leaves a message; a robocaller usually does not.
- Look the number up with the box above before you call back, because calling back tells a robocaller your line is live.
- Hang up on anyone who wants gift cards, crypto or a wire transfer, or asks you to read out a code that was just texted to you.
- Report unwanted robocalls at reportfraud.ftc.gov, or paste a suspicious message into our free scam checker.
The area codes closest to 650 are 510, 408 and 925.
This list measures the distance between the centres of each area, across state lines, and shows codes that share one area together.
California has 40 other area codes.
These are the questions people ask most about area code 650.
Where is area code 650?
650 covers Palo Alto, San Mateo, South San Francisco and Redwood City and 8 more places in California. In the 650 area, phone numbers are given out most in San Mateo County, then Santa Clara County and the City and County of San Francisco.
What state is area code 650 in?
California. 650 is a California area code on Pacific Time.
What cities use area code 650?
The places holding the most 650 prefixes are Palo Alto, San Mateo, South San Francisco, Redwood City, Los Altos, Millbrae, San Francisco and Half Moon Bay, out of 12 places in all. The count comes from NANPA's prefix assignments as of October 1, 2026.
Which phone company owns area code 650?
No single phone company owns 650. NANPA's records show Pacific Bell (AT&T) holds the most 650 prefixes, 272 of 716, followed by AT&T Mobility and T-Mobile. Numbers move between carriers, so check one exact number with a carrier lookup.
What time zone is area code 650 in?
650 is on Pacific Time.
When did area code 650 start?
650 went into service on August 2, 1997, when it was split off from 415.
How do I dial a 650 number?
Local calls need 1, then the area code, then the number: 1-650-555-0142.
Is 650 a toll-free number?
No. 650 is a regular area code for Palo Alto and San Mateo in California, not a toll-free one. The toll-free codes in North America are 800, 833, 844, 855, 866, 877 and 888.
What area codes are near 650?
The closest are 510/341 (Oakland, California), 408/669 (San Jose, California), 925 (Walnut Creek, California) and 415/628 (San Francisco, California), measured between the centres of each area.
Who called me from a 650 number?
Enter the full 10-digit number in the lookup above. It returns the listed owner where there is a public record, where the number is registered, and whether it is a mobile, a landline or a VoIP line.
Is area code 650 a scam?
650 is a real California area code, so the code itself is not a warning sign. Scam callers fake local-looking numbers on purpose, so judge the call by what the caller asks for, and look the number up before calling back.
Put this lookup on your site: our free area code widget takes two lines of code and shows any US area code's state, time zone and local time.
Source: NANPA, the North American Numbering Plan Administrator: its area code database and prefix assignments, as of October 1, 2026.