Find out who called from an unknown San Mateo number using our free reverse phone lookup. Enter any 10-digit number with area code 650 to search for caller name, address, and more.
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Got a phone call or message from a San Mateo, California phone number you don't recognize? Before you answer, call back, or reply, use our phone number lookup service to find out who's really on the other end, is it a scam, legitimate business or someone you'd rather avoid.
The total population of San Mateo, CA, is 105,661. That's thousands of potential callers you might not recognize: local business contacts, neighbors, service providers, or people from across the city.
An unknown caller could be anyone — a sales call, an old friend, someone you actually want to talk to. Without caller identification, you either ignore potentially important calls or answer ones you'd rather avoid.
Scam and spam calls continue to impact CA residents which, according to the National Do Not Call Registry Data Book, filed 287,916 complaints about unwanted calls in 2024. Of these, 161,548 were robocalls and 98,127 involved live callers. The top complaint topics included imposters (27,125), reducing debt (20,756), medical and prescriptions (13,374).
According to FTC 2024 data, CA residents reported 238,705 fraud cases in 2024, resulting in $1,678,703,608 in losses, with a median loss of $542 per victim. Given that more than 1 in 3 fraud attempts occur over the phone, verifying who is calling is critical for preventing financial losses.
If you receive fraudulent calls or suspect a scam attempt, report it to reportfraud.ftc.gov or local police department using the following contacts:
Additionally, protect your household by registering your phone numbers at donotcall.gov or by calling 1-888-382-1222 from the number you wish to register.
Have you received a call from a business but aren’t sure if it’s really them? San Mateo is primarily located in San Mateo County, which, according to U.S. Census Bureau data, includes 18,903 firms and 21,632 establishments employing 464,365 people.
| County | Percent of City | Firms | Establishments |
|---|---|---|---|
| San Mateo | 100.00% | 18903 | 21632 |
Use our service to reverse-lookup unknown California phone numbers to verify whether they actually belong to a company before answering or calling back. By cross-referencing phone numbers with local business directories, you can ensure you’re dealing with legitimate local businesses, services, contractors, or vendors—not scammers spoofing local numbers to gain your trust.
California phone numbers use area codes 650. Click a code to look up numbers starting with it.
Phone numbers reported as unwanted calls to the FTC by San Mateo residents in the last 30 days.
(888) 269-4978
Reducing your debt (credit cards, mortgage, student loans)
2 reports ·
(877) 232-8644
Other
1 report ·
(434) 736-1176
Reducing your debt (credit cards, mortgage, student loans)
1 report ·
(650) 308-1461
Other
1 report ·
(844) 515-1201
Reducing your debt (credit cards, mortgage, student loans)
1 report ·
(866) 398-3898
Reducing your debt (credit cards, mortgage, student loans)
1 report ·
(989) 943-4137
Other
1 report ·
(415) 604-1043
Other
1 report ·
(415) 857-5442
Other
1 report ·
(833) 854-2927
Other
1 report ·
If you receive fraudulent calls or suspect a scam attempt, report it to reportfraud.ftc.gov or local police department using the following contacts:
Local Time
02:54 AM
Date
Tuesday, April 14, 2026
Time Zone
PDT
San Mateo has a population of 105661 people. Sex ratio is 100.10 males per 100 females.
The median age in San Mateo is 34.8 years.
| Age Groups | Population |
|---|---|
| Under 5 years | 6971 |
| 5 to 9 years | 5935 |
| 10 to 14 years | 5452 |
| 15 to 19 years | 4596 |
| 20 to 24 years | 5601 |
| 25 to 29 years | 8198 |
| 30 to 34 years | 9691 |
| 35 to 39 years | 9013 |
| 40 to 44 years | 7128 |
| 45 to 49 years | 6770 |
| 50 to 54 years | 6612 |
| 55 to 59 years | 5860 |
| 60 to 64 years | 5412 |
| 65 to 69 years | 4325 |
| 70 to 74 years | 3747 |
| 75 to 79 years | 2782 |
| 80 to 84 years | 2490 |
| 85 years and over | 3036 |
| Racial/Ethnic Groups | Percent |
|---|---|
| White | 43826 |
| Black or African American | 1815 |
| American Indian and Alaska Native | 866 |
| Native Hawaiian and Other Pacific Islander | 1700 |
| Some Other Race | 16065 |
| Two or more races | 13342 |