636 Area Code: St. Charles, Missouri
Area code 636 serves St. Charles, Harvester and Chesterfield, Missouri in the Central time zone, in service since 1999. Consumers have filed 2,682 unwanted-call complaints against 2,295 different 636 numbers, 309 of them with the FTC in the last 30 days. Look up the exact number that called you below.
Area code 636 at a glance
- State
- Missouri
- Main cities
- St. Charles, Harvester, Chesterfield, Manchester, O'Fallon, Fenton + 38 more
- Counties
- St. Charles County, St. Louis County, Jefferson County, Franklin County + 3 more
- Local time
- —Central
- In service since
- May 22, 1999
- Split from
- 314
- Local dialing
- 7 digits allowed
- Exchanges
- 46 rate centers, 435 prefixes
Sources: NANPA area code and central office code records (refreshed weekly); cities and counties matched from US Census Bureau and USGS place names.
Most-reported 636 numbers
Ranked by FTC Do Not Call complaints this month, then all-time FTC and FCC complaints. Only numbers with enough complaints for a full report page are listed. Click one for what it was reported for and where.
What calls from 636 numbers are about
980 FTC Do Not Call complaints about 636 numbers since Jul 24. The most common named subject is impostor calls (people pretending to be a government agency, a business or family), at 10% of complaints (62% of those were recorded messages). Overall, 59% of callers who answered said the call was a robocall.
FTC complaint subjects
- Other / unspecified49350%
- Impostor (government, business, family)10010%
- Medical & prescriptions9410%
- Debt reduction909%
- Dropped call / no message667%
- No subject given546%
- Home improvement & cleaning404%
FCC complaints by call type, last 2 years
- Live Voice26664%
- Prerecorded Voice13532%
- Text Message174%
Live-voice calls are from a person; prerecorded calls are robocalls.
When 636 spam calls come in
31% of complaints that give a call time describe calls between 10am and 1pm. 94% came Monday to Friday, most on Tuesdays, the pattern of call-center robocall campaigns that run on business hours. Times are as consumers reported them to the FTC.
By hour of the day
By day of the week
Is it getting worse?
301 FTC complaints about 636 numbers in the last four weeks, down 9% on the four weeks before. FCC complaints about 636 numbers peaked in 2025 (306); the FTC's daily Do Not Call data has carried most of the volume since mid-2026.
FTC complaints per week
FCC complaints per year
Years shown as '15 to '26; the current year is partial.
Who gets these calls
56% of the FTC complaints about 636 numbers came from people whose own phone number also starts with 636, and 73% from Missouri. Calls that look local to the person receiving them are the signature of neighbor spoofing: robocallers display a number from your own area code because you're more likely to answer.
Where complainants live
- Missouri71973%
- Florida253%
- Texas232%
- Ohio182%
- Illinois182%
What people with 636 numbers report
People whose own number starts with 636 filed 952 FTC complaints since Jul 24. 57% were about calls showing another 636 number. The most common named subject was debt-relief pitches.
Area codes on the calls they reported
- 636 (same code)54757%
- 314738%
- 833 (toll-free)374%
- 816172%
- 573152%
Busiest 636 prefixes this month
FTC complaints in the last 30 days, grouped by the first six digits. When one prefix collects complaints about many different numbers, a campaign is usually cycling through that block. The carrier is who NANPA assigned the prefix to, not who made the calls.
| Prefix | Complaints | Numbers | Carrier | Exchange |
|---|---|---|---|---|
| (636) 234-xxxx | 13 | 6 | Level 3 (Lumen) | Union |
| (636) 425-xxxx | 12 | 11 | PAETEC (Windstream) | Portage Des Sioux |
| (636) 407-xxxx | 11 | 10 | Onvoy (Sinch) | De Soto |
| (636) 200-xxxx | 11 | 10 | Onvoy (Sinch) | Manchester |
| (636) 400-xxxx | 10 | 10 | Onvoy (Sinch) | Portage Des Sioux |
Carriers operating in 636
NANPA has assigned 435 636 prefixes (NPA-NXX central-office codes) across 46 rate centers: 21% to wireless carriers, 78% to landline and VoIP operators; 84% are pooled blocks shared by several carriers. 6 prefixes were assigned in the last 12 months (newest 2026-09-10). The carrier holding a prefix is who the number was issued through. It says nothing about who is calling, since caller ID is routinely spoofed.
| Carrier | Type | Prefixes | Rate centers | Newest assignment |
|---|---|---|---|---|
| Southwestern Bell (AT&T) | Incumbent landline (ILEC) | 110(25%) | 24 | 2013-04-18 |
| Brightspeed of Missouri, LLC | Incumbent landline (ILEC) | 49(11%) | 21 | 2020-05-14 |
| Onvoy (Sinch) | Competitive / VoIP (CLEC) | 36(8%) | 22 | 2026-09-10 |
| T-Mobile USA | Wireless | 35(8%) | 15 | 2026-04-02 |
| Level 3 (Lumen) | Competitive / VoIP (CLEC) | 29(7%) | 18 | 2004-12-07 |
| AT&T Mobility (New Cingular Wireless PCS) | Wireless | 29(7%) | 14 | 2025-09-19 |
| MCImetro (Verizon Business) | Competitive / VoIP (CLEC) | 28(6%) | 9 | 2020-07-27 |
| PAETEC (Windstream) | Competitive / VoIP (CLEC) | 25(6%) | 19 | 2013-08-19 |
| Verizon Wireless (Cellco Partnership) | Wireless | 20(5%) | 10 | 2024-02-23 |
| Charter (Spectrum Voice) | Competitive / VoIP (CLEC) | 18(4%) | 13 | 2016-04-05 |
| Teleport Communications America, LLC | Competitive / VoIP (CLEC) | 15(3%) | 14 | 2018-04-26 |
| Peerless Network | Competitive / VoIP (CLEC) | 4(1%) | 4 | 2019-03-06 |
Largest rate centers (exchanges) by prefixes: St. Charles (44), Chesterfield (36), Harvester (36), Manchester (27), O'Fallon (24), Fenton (16), St. Peters (15), Valley Park (14), Wentzville (14). Source: NANPA Central Office Code Utilized Assignments (public, refreshed weekly).
What to do about calls from 636 numbers
Before you call back
- Impostor (government, business, family) is the top named complaint here. Hang up and call the agency, bank or relative back on a number you already know. Government agencies don't demand payment by gift card, wire transfer or crypto. Read about Social Security impostor calls and fake bank fraud calls.
- Look up the full number above. A missed call from 636 with no voicemail is usually a robocall; anyone who needs you will leave a message.
- If it looks like a neighbor's number, it may be spoofed. See calls from your own area code.
- Block repeat callers: iPhone, Android, or your carrier's free filter (Verizon, AT&T, T-Mobile).
Report it in Missouri
- Unwanted sales calls and robocalls: donotcall.gov (FTC). Scams and fraud: ReportFraud.ftc.gov.
- Spoofing, texts and call-blocking problems: FCC consumer complaints.
- State complaints: Missouri Attorney General.
- Missouri is one of the states that maintains its own Do Not Call registry alongside the federal National Do Not Call Registry, so telemarketers calling Missouri numbers are expected to check both lists. Registering on the federal list at donotcall.gov is free and never expires; the state list is administered separately and may have its own registration process and renewal period.
Your FTC and FCC reports are published (without your name or number) in the datasets this page is built from. How to report unwanted calls.
Area code 636: questions answered from the data
Where is area code 636?
Area code 636 serves St. Charles, Harvester and Chesterfield, Missouri, covering St. Charles County, St. Louis County and Jefferson County and 4 more counties. It has been in service since May 22, 1999. It was split from area code 314.
What time zone is area code 636 in?
Area code 636 is in the Central time zone (UTC−6, or UTC−5 during daylight saving time). The current local time is shown at the top of this page.
What are calls from 636 numbers usually about?
Since Jul 24, consumers filed 980 FTC Do Not Call complaints about 636 numbers. The most common named subject was impostor calls (people pretending to be a government agency, a business or family): 10% of complaints, 62% of them recorded messages. Across all subjects, 59% of callers who answered the question said the call was a robocall.
When do 636 spam calls happen?
31% of the complaints that give a call time describe calls between 10am and 1pm, and 94% came on weekdays, most often on Tuesday. Times are as consumers reported them.
Are calls from 636 numbers really local?
Not necessarily. 56% of the FTC complaints about 636 numbers came from people whose own phone number also starts with 636, and 73% from Missouri. Calls that look local to the person receiving them are the signature of neighbor spoofing: robocallers display a number from your own area code because you're more likely to answer.
Are 636 robocalls increasing?
In the four weeks to Oct 20, consumers filed 301 FTC complaints about 636 numbers, 9% fewer than the four weeks before.
How do I report a 636 scam call in Missouri?
Report unwanted sales calls and robocalls to the FTC at donotcall.gov, and scams to ReportFraud.ftc.gov. The FCC takes complaints at consumercomplaints.fcc.gov. In Missouri, the Missouri Attorney General also handles consumer complaints about scam calls. Reports feed the public data this page is built from.
Other Missouri area codes
Sources: FTC Do Not Call complaints (unverified consumer reports), published every weekday and available here from Jul 24; FCC Consumer Complaint Data, public record, imported nightly; NANPA numbering records. A number appearing here means consumers reported calls that displayed it. Caller ID can be spoofed.