Colorado area codes: full list with cities and how to dial
Colorado has roughly 5.9 million residents, and its phone numbers are organized into 6 area codes under the North American Numbering Plan. Colorado is served by 6 active geographic area codes, anchored by 303 in the Denver area. The Denver and northern/western Colorado regions use overlays requiring ten-digit dialing. Every Colorado number is dialed as +1, then the three-digit area code, then a seven-digit local number. With Phonecall you can call any Colorado landline or mobile straight from your browser. There is no app to install, no SIM, and no subscription. You see the per-minute rate before you dial, billing is by the second, and your first call is free.
Call Colorado from your browserAll Colorado area codes
6 active geographic area codes in service across Colorado.
| Area code | Primary cities and region | Example number |
|---|---|---|
| 303 | Greater Denver metro (overlay of 303/720/983) | +1 (303) 555-0100 |
| 720 | Denver metro (overlay of 303) | +1 (720) 555-0100 |
| 983 | Denver metro (overlay of 303/720) | +1 (983) 555-0100 |
| 719 | Colorado Springs, Pueblo (southeastern and south-central Colorado) | +1 (719) 555-0100 |
| 970 | Fort Collins, Grand Junction, Vail, Aspen (northern and western Colorado) | +1 (970) 555-0100 |
| 748 | Northern and western Colorado (overlay of 970) | +1 (748) 555-0100 |
Example numbers use the reserved 555-0100 range and are for illustration only.
How to call Colorado from abroad
Every Colorado phone number is part of the +1 North American calling zone. To reach one from outside the United States, dial three parts in order:
- 1. Your exit code, then +1 — the US country code.
- 2. The three-digit area code — for example 303 for the Denver area.
- 3. The seven-digit local number.
Example, full international format:
+1 (303) 555-0100
With Phonecall you skip the exit codes entirely. Enter the number in international format and we connect the call from your browser, billed by the second from $0.03/min, with no SIM, no app, and no monthly fee.
Why Colorado has multiple area codes
The Denver and northern/western Colorado regions use overlays requiring ten-digit dialing.
When a region runs low on available numbers, the phone system adds capacity in one of two ways. A split divides the old region geographically and gives part of it a brand-new area code. An overlay keeps the existing code and layers a second one on top of the same area, which is why a single city can have several area codes and why ten-digit dialing becomes the norm. Either way, the number you dial always stays the same length: +1, the area code, then seven digits.
6
active area codes
~5.9 million
residents (approx.)
Denver
largest city
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Colorado area codes: frequently asked questions
What is the main area code for Denver?
Denver, the largest city in Colorado, is primarily served by area code 303 (Greater Denver metro (overlay of 303/720/983)). Colorado has 6 area codes in total, listed in full above.
How do I dial a Colorado number from another country?
Dial your international exit code, then +1 (the US country code), then the three-digit Colorado area code, then the seven-digit local number. With Phonecall you just enter the number in international format and we connect the call from your browser, from $0.03/min.
How many area codes does Colorado have?
Colorado currently has 6 active geographic area codes in service. The Denver and northern/western Colorado regions use overlays requiring ten-digit dialing.