720 area code
Denver area, Mountain Time.Area code 720 covers Denver, Longmont, Fort Lupton and 10 more places in Colorado, on Mountain Time. 303 and 983 cover the same area.
Right now in Denver
Mountain Time (MST, UTC-7; MDT, UTC-6 in summer)
Calling hours: Every day, 8 AM to 9 PM (the federal rule)
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Where 720 numbers come from
Numbers are issued by rate center, a billing area named for its main town. 720 has 13. Each one's share is how many 720 numbers start there. Its biggest metro area is Denver-Aurora-Centennial, CO.
- Denver86%
- Longmont5%
- Fort Lupton2%
- Georgetown1%
Also: Deckers, Allenspark-Lyons, Keenesburg, Hudson, Deer Trail, Strasburg, Bennett, Byers, Roggen
Share of exchanges (blocks of 10,000 numbers). Source: NANPA rate center and exchange reports, November 10, 2026
When can you call a 720 number?
Sales calls to homes and cell phones have legal hours, set by the federal rule. Hold every 720 number to them, since you can't tell a work line from a personal cell.
What applies to 720Every day, 8 AM to 9 PM
- Federal (TCPA and FTC rule)Every day, 8 AM to 9 PMCalls to residential and mobile numbers. Most calls to businesses are exempt from the FTC's rule.47 CFR 64.1200(c)(1); 16 CFR 310.4(c) (opens in a new tab)
Local time comes from the area code, not from where the person is today. Mobiles keep their number when they move. Calling hours here are a guide, not legal advice. Every state's calling hours, with sources
720 and 303 and 983
720 went into service on June 1, 1998. 720, 303 and 983 cover the same area, so new numbers can get any of them and neighbors can have different area codes. 720 holds 49% of the area's exchanges, the most of any code here. Local calls take all 10 digits.
- 1947303 overlay
- 1998720 starts
- 2022983 overlay
Source: NANPA area code database
Other Colorado area codes
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720 area code FAQ
What area code is 720?
720 is a Colorado area code for Denver, Longmont, Fort Lupton, Georgetown and 9 more places.
What time zone is the 720 area code in?
Mountain Time (MST, UTC-7; MDT, UTC-6 in summer).
Is 303 the same as 720?
Same area, different code. 720, 303 and 983 cover the same area (an overlay), so new numbers can get any of them and local calls take all 10 digits.
What are the calling hours for 720 numbers?
Every day, 8 AM to 9 PM, local time, under the federal rule.
When did the 720 area code start?
On June 1, 1998.
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