Area codes / Colorado
Colorado area codes
Colorado has 6 area codes in service, in the Mountain time zone. Pick one for a local business number your Colorado customers recognize.
Every Colorado area code
Picking a Colorado area code
303 is among the original area codes created in 1947. 5 Colorado area codes share their region with an overlay, so a new number there may come in either code; both ring the same area, and calls within it are dialed with all ten digits.
Already have a Colorado number customers know? Move it to Onyx Phone for free, and keep answering while it moves.
Getting started
- Create a login and pick a plan. Checkout saves a card for the 7-day free trial, and nothing is charged until it ends.
- Confirm your business and its 911 address, and get a local number on the spot. Bringing your own number? You answer on a temporary one while it moves over, for free.
- Choose where calls ring, write what callers hear, invite your team, and register for texting. Then answer in the browser, the iPhone and Android apps, or a desk phone. How it works has the details.
Included on every plan
Starter is $17, Business is $29, Scale is $42 per user a month, or less billed yearly. The plan includes a business number for each user and unlimited calling and texting in the US and Canada. Every plan starts with a 7-day free trial, and moving your current number over is free.
Area code data from NANPA, file of October 24, 2026.