720 Area Code: Denver, Colorado
Area code 720 serves Denver and Longmont, Colorado in the Mountain time zone, in service since 1998. Consumers have filed 8,789 unwanted-call complaints against 6,709 different 720 numbers, 902 of them with the FTC in the last 30 days. Look up the exact number that called you below.
Area code 720 at a glance
- State
- Colorado
- Main cities
- Denver, Longmont + 6 more
- Counties
- Denver County, Boulder County, Weld County, Clear Creek County + 3 more
- Local time
- —Mountain
- In service since
- June 1, 1998
- Overlay of
- 303
- Overlay code
- 983 (2022)
- Local dialing
- 10 digits (area code + number)
- Exchanges
- 12 rate centers, 785 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 720 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 720 numbers are about
2,413 FTC Do Not Call complaints about 720 numbers since Jul 24. The most common named subject is debt-relief pitches, at 11% of complaints (81% of those were recorded messages). Overall, 64% of callers who answered said the call was a robocall.
FTC complaint subjects
- Other / unspecified1,09846%
- Debt reduction26011%
- Dropped call / no message2239%
- Medical & prescriptions1918%
- Impostor (government, business, family)1888%
- Home improvement & cleaning1536%
- No subject given1456%
FCC complaints by call type, last 2 years
- Live Voice29342%
- Prerecorded Voice26438%
- Text Message13419%
19% of recent FCC complaints about 720 numbers are about text messages, not calls.
When 720 spam calls come in
30% of complaints that give a call time describe calls between 9am and 12pm. 93% came Monday to Friday, most on Wednesdays, 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?
892 FTC complaints about 720 numbers in the last four weeks, up 23% on the four weeks before. FCC complaints about 720 numbers peaked in 2017 (917); 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
68% of the FTC complaints about 720 numbers came from Colorado residents, but only 42% from people with 720 numbers themselves. The calls are mostly regional rather than aimed at 720 phones specifically.
Where complainants live
- Colorado1,63568%
- California914%
- Florida763%
- Texas582%
- Illinois442%
What people with 720 numbers report
People whose own number starts with 720 filed 3,511 FTC complaints since Jul 24. 29% were about calls showing another 720 number. The most common named subject was debt-relief pitches.
Area codes on the calls they reported
- 720 (same code)1,00629%
- 833 (toll-free)1845%
- 877 (toll-free)1715%
- 855 (toll-free)1344%
- 866 (toll-free)1324%
Likely campaigns using 720 numbers
Groups of numbers that drew the same FTC complaint in the same pattern over the last 60 days. The grouping is statistical and doesn't identify who is calling.
Busiest 720 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 |
|---|---|---|---|---|
| (720) 604-xxxxcampaign | 16 | 16 | Bandwidth.com | Denver |
| (720) 513-xxxx | 15 | 12 | Onvoy (Sinch) | Denver |
| (720) 721-xxxx | 13 | 12 | The Voice Application Network, LLC | Denver |
| (720) 543-xxxx | 12 | 12 | Peerless Network | Denver |
| (720) 806-xxxx | 11 | 11 | Peerless Network | Deckers |
Carriers operating in 720
NANPA has assigned 785 720 prefixes (NPA-NXX central-office codes) across 12 rate centers: 39% to wireless carriers, 60% to landline and VoIP operators; 83% are pooled blocks shared by several carriers. The newest assignment was 2024-09-03. 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 |
|---|---|---|---|---|
| T-Mobile USA | Wireless | 132(17%) | 3 | 2024-01-16 |
| Qwest (CenturyLink / Lumen) | Incumbent landline (ILEC) | 103(13%) | 3 | 2017-07-21 |
| AT&T Mobility (New Cingular Wireless PCS) | Wireless | 92(12%) | 3 | 2024-09-03 |
| Verizon Wireless (Cellco Partnership) | Wireless | 75(10%) | 4 | 2022-09-16 |
| Bandwidth.com | Competitive / VoIP (CLEC) | 55(7%) | 7 | 2024-04-03 |
| Onvoy (Sinch) | Competitive / VoIP (CLEC) | 55(7%) | 8 | 2022-11-16 |
| MCImetro (Verizon Business) | Competitive / VoIP (CLEC) | 51(6%) | 2 | 2017-04-03 |
| Level 3 (Lumen) | Competitive / VoIP (CLEC) | 46(6%) | 4 | 2020-08-17 |
| Teleport Communications America, LLC | Competitive / VoIP (CLEC) | 31(4%) | 2 | 2021-10-25 |
| Comcast (Xfinity Voice) | Competitive / VoIP (CLEC) | 21(3%) | 5 | 2022-03-25 |
| Electric Lightwave LLC dba Allstream | Competitive / VoIP (CLEC) | 17(2%) | 1 | 2014-10-15 |
| Level 3 (Lumen) | Competitive / VoIP (CLEC) | 17(2%) | 1 | 2017-09-01 |
Largest rate centers (exchanges) by prefixes: Denver (678), Longmont (39), Fort Lupton (14), Georgetown (11), Allenspark–Lyons (10), Deckers (10), Keenesburg (9), Hudson (8), Deer Trail (3), Bennett (1). Source: NANPA Central Office Code Utilized Assignments (public, refreshed weekly).
What to do about calls from 720 numbers
Before you call back
- Debt reduction is the top named complaint here. Don't pay upfront fees for debt relief; the FTC's Telemarketing Sales Rule bans them. Talk to your lender or a nonprofit credit counselor instead. Read about debt-relief robocalls.
- Look up the full number above. A missed call from 720 with no voicemail is usually a robocall; anyone who needs you will leave a message.
- Block repeat callers: iPhone, Android, or your carrier's free filter (Verizon, AT&T, T-Mobile).
Report it in Colorado
- 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: Colorado Attorney General.
- Colorado is one of the states that maintains its own Do Not Call registry alongside the federal National Do Not Call Registry, so telemarketers calling Colorado 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 720: questions answered from the data
Where is area code 720?
Area code 720 serves Denver and Longmont, Colorado, covering Denver County, Boulder County and Weld County and 4 more counties. It has been in service since June 1, 1998.
What time zone is area code 720 in?
Area code 720 is in the Mountain time zone (UTC−7, or UTC−6 during daylight saving time). The current local time is shown at the top of this page.
Which area codes overlay 720?
983 (in service 2022) serves the same area as 720. New numbers there can be issued with any of these codes, and local calls need all 10 digits. A spoofed call can display any of them.
What are calls from 720 numbers usually about?
Since Jul 24, consumers filed 2,413 FTC Do Not Call complaints about 720 numbers. The most common named subject was debt-relief pitches: 11% of complaints, 81% of them recorded messages. Across all subjects, 64% of callers who answered the question said the call was a robocall.
When do 720 spam calls happen?
30% of the complaints that give a call time describe calls between 9am and 12pm, and 93% came on weekdays, most often on Wednesday. Times are as consumers reported them.
Are calls from 720 numbers really local?
Not necessarily. 68% of the FTC complaints about 720 numbers came from Colorado residents, but only 42% from people with 720 numbers themselves. The calls are mostly regional rather than aimed at 720 phones specifically.
Are 720 robocalls increasing?
In the four weeks to Oct 20, consumers filed 892 FTC complaints about 720 numbers, 23% more than the four weeks before.
How do I report a 720 scam call in Colorado?
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 Colorado, the Colorado Attorney General also handles consumer complaints about scam calls. Reports feed the public data this page is built from.
Overlay and nearby 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.