Area code 303

Area code 303 at a glance

Area code 303 is a geographic area code in Colorado, in service since January 1, 1947, according to the North American Numbering Plan Administrator (NANPA). It is an overlay: 303 and 720 and 983 cover the same territory, so neighbors on the same street can have different area codes. It is in the Mountain time zone. The places with the most assigned exchanges include Denver, Longmont, Fort Lupton, Keenesburg, and Hudson. By population, its largest named places are Denver, Longmont, Fort Lupton, Bennett, and Keenesburg.

Where 303 numbers are local

303 holds 26% of the 3,055 central office codes assigned in Colorado, the 2nd most of the state's 6 codes. 8 Census places could be matched to rate centers with 303 exchanges; the most populous are Denver (729,000), Longmont (99,818), Fort Lupton (9,948), and Bennett (3,916). For a storefront or service area inside 303, the place pages show which prefixes are rated local there.

How calls are dialed in 303

According to NANPA's dialing-plan data, local calls within 303 are dialed as ten digits (area code plus number) and toll calls as 1 plus ten digits. Ten-digit local dialing means the area code is part of how customers save and recognize your number, so print it in full everywhere. NANPA's dialing-plan note for this code reads: "1+10 permissible at each service providers discretion"

Phone companies in area code 303

27 carriers hold the 784 central office codes assigned in 303. Qwest Corporation has the most, with 448 (57%). 228 of the codes (29%) are pooled, meaning the code holder shares blocks of 1,000 numbers with other carriers instead of using all 10,000 itself. Numbers can move between carriers through porting, so a code's holder tells you where the block started, not where every number lives now.

Local calling areas in 303

NANPA assigns each central office code to a rate center, the local calling area that decides whether a call is local or toll. 303 has codes in 13 rate centers. The table lists the rate centers with the most codes, with the matching Census place where the abbreviation could be matched.

How full is area code 303?

An area code has 800 possible central office codes that start with 2 through 9, a few of which are reserved (such as N11 service codes and 555). 784 are assigned in 303, 98% of 800. 8 were assigned in 2020 or later.

Getting a 303 number for your business

For $99 a month, Callata puts a team of up to 5 on one plan ($20 for each person after that): up to 3 local numbers, unlimited inbound calls, a pooled allowance of 1,500 outbound US and Canada minutes per user, browser and cell calling, voicemail transcription with urgency triage, recorded calls with AI summaries and business-hours routing, with E911 on every number.

If you already have a number in area code 303, porting it to Callata is free. Texting from a local number requires a one-time carrier registration (10DLC, $49), and the numbers available in any area code depend on carrier inventory when you choose them.

Optional AI agents (receptionist, sales, support or scheduler) can answer calls after hours or when nobody picks up, take messages, text, email and transfer to your team. They are billed from prepaid AI minutes at $0.25 per minute, identify themselves as AI, and may only place outbound calls to people who consented, between 8am and 9pm.