Area code
Area code 303 — Denver, CO
Colorado · in service since 1947
Area code 303 covers Denver, CO. It is an overlay: 720, 983 serve the same area, so neighbors can have different area codes.
Local time in Denver
Spam reports from Sep 23 – Oct 22, 2026
High #60 of 461 codes
816 FTC complaints
Consumer reports, not verified by the FTC.
See the reports- Time zoneMountain Time
- Local calls10 digits
- Prefixes800 assigned
- Runs out~2Q 2069
- Unwanted call?Block & report
Spam call reports about 303 numbers
Complaints by week
Sep 11 – Oct 22, 2026Show as table
| Week starting | Complaints |
|---|---|
| Sep 7 (3 days) | 33 |
| Sep 14 | 205 |
| Sep 21 | 217 |
| Sep 28 | 202 |
| Oct 5 | 179 |
| Oct 12 | 136 |
| Oct 19 (4 days) | 159 |
Compared with all codes
- Robocalls
- 72%all codes 75%
- Callers with the same code
- 81%all codes 35%
- Rank by complaints
- #60of 461 · top quarter
- FCC complaints, Oct 2025 – Sep 2026
- 2,2188 about text messages
What the calls were about
Sep 11 – Oct 22, 2026
| Subject | Complaints | |
|---|---|---|
| Medical & prescriptions | 172 15% | |
| Dropped call or no message | 97 9% | |
| Calls pretending to be government, businesses, or family and friends | 79 7% | |
| Home improvement & cleaning | 55 5% | |
| Warranties & protection plans | 45 4% | |
| Reducing your debt (credit cards, mortgage, student loans) | 39 3% |
Where the people who complained live
Sep 11 – Oct 22, 2026
| State | Complaints | |
|---|---|---|
| Colorado | 1,011 89% | |
| California | 9 1% | |
| Ohio | 9 1% | |
| Texas | 8 1% | |
| Florida | 7 1% |
October 2026 (partial) report · most reported
Consumer reports, not verified by the FTC · source
Source: FTC Do Not Call complaints created Sep 11 – Oct 22, 2026. They are reported by consumers and are not verified by the FTC; caller ID can be spoofed (how we count).
Source: FCC Consumer Complaints data, unwanted calls filed Oct 1, 2025 – Sep 30, 2026, by caller ID; not verified by the FCC.
Area code 303 location and prefixes
| Exchange (NANPA) | Place | County | Prefixes |
|---|---|---|---|
| DENVER | Denver | Denver County | 736 |
| LONGMONT | Longmont | spans 2 counties | 18 |
| FORTLUPTON | Fort Lupton | Weld County | 11 |
| DECKERS | — | — | 5 |
| KEENESBURG | Keenesburg | Weld County | 3 |
| ALLNSPKLYN | — | — | 2 |
| DEER TRAIL | Deer Trail | Arapahoe County | 2 |
| GEORGETOWN | Georgetown | Clear Creek County | 2 |
| HUDSON | Hudson | Weld County | 2 |
| BENNETT | Bennett | spans 2 counties | 1 |
Plus 3 smaller exchange areas.
Source: NANPA CO codes of Oct 23, 2026; places: U.S. Census Bureau, matched by DialWhere (how).
NANPA record
- Location
- Colorado
- Assigned by NANPA
- 1947
- Local dialing
- 10 digits (NANPA: 10D)
- NANPA planning letters
- PL-563
Source: NANPA, NPA database of Oct 24, 2026.
Is 303 running out of numbers?
Previous forecast (October 2025): 2071, moved earlier by 2 years.
Forecast exhaust year by edition
Source: NANPA NRUF forecast, April 2026 edition.
Who holds 303 prefixes
The five largest of 29 original holders
As listed by NANPA, not today’s carrier.
| Holder (as listed) | Prefixes | |
|---|---|---|
| Qwest Corporation | 449 56% | |
| Verizon Wireless | 60 8% | |
| Level 3 Communications, LLC | 58 7% | |
| T-Mobile USA, Inc. | 39 5% | |
| New Cingular Wireless PCS, LLC | 35 4% |
Source: NANPA CO codes of Oct 23, 2026.
Questions about area code 303
What area code is 303?
A Colorado area code, in service since 1947.
Where is 303 area code, and what time zone is it in?
Denver, CO; Mountain Time.
Why am I getting spam calls from 303?
816 FTC complaints from Sep 23 – Oct 22, 2026, most often about medical & prescriptions (not verified by the FTC; caller ID can be spoofed).
Will 303 get a new area code?
NANPA forecasts exhaust in 2Q 2069; no relief planning listed.