Frequently Asked Questions
Area code 623 primarily covers the western Phoenix metropolitan area, including Avondale, Glendale, Peoria, Surprise, Sun City, and other smaller communities in the West Valley. While Avondale is the primary city, 623 encompasses a broad region due to growth and demand for telecommunications services.
Dial "1" followed by the full 10-digit number (1-623-XXX-XXXX). This format applies to long-distance calls made from outside the 623 area code. Remember to always include the "1" before the area code and the 7-digit number.
10-digit dialing became mandatory in 2023 due to an overlay implementation. This overlay combined area codes 602, 480, and 623 to address number exhaustion in 602 and 480, eliminating geographic boundaries and requiring 10-digit dialing for all calls within these area codes.
Area code 623 was introduced in 1999. Initially, area code 602 served all of Arizona, then 520 was added in 1995. The further division in 1999, creating 480 and 623, aimed to accommodate the growing population of the Phoenix metropolitan area.
The area code for Avondale, Arizona, is 623. However, due to the 2023 overlay, Avondale is also served by area codes 602 and 480. 10-digit dialing is necessary for all calls within these overlaid area codes.
Area code 623 is in Mountain Standard Time (MST), which is 7 hours behind Coordinated Universal Time (UTC-7). Arizona observes MST for most of the year, except during Daylight Saving Time, when it switches to Mountain Daylight Time (MDT).
Use 10-digit dialing, meaning you dial the full 10-digit number (623-XXX-XXXX) even for local calls within the same area code. This practice became mandatory in 2023 after the implementation of the overlay.
The overlay, implemented in 2023, combined area codes 602, 480, and 623, removing geographic boundaries. This means multiple area codes serve the same region, making 10-digit dialing mandatory for all calls, even local ones.
No, you can no longer dial just 7 digits in area code 623. The 2023 overlay requires 10-digit dialing for all calls, including local calls within the 623 area code. This ensures calls connect correctly within the overlaid region.
You can find additional information on area codes and telecommunications regulations on the Federal Communications Commission (FCC) website or specialized sites like allareacodes.com, which provide specific details about area code 623, demographics, and carrier information.
Dial "0" followed by the full 10-digit number you want to reach (0-623-XXX-XXXX). While operator-assisted calls are less common today, this option is still available for calls needing operator assistance.
Area Code 623: Avondale, Arizona Coverage and Usage
What is Area Code 623?
Area code 623 is a telephone area code serving the western Phoenix metropolitan area in Arizona. The 623 area code covers major cities including Avondale, Glendale, Peoria, Surprise, Sun City, and Goodyear. As of 2023, area code 623 is part of an overlay complex with area codes 602 and 480, requiring mandatory 10-digit dialing for all local calls throughout the Phoenix metro area. The overlay eliminated geographic boundaries between the three area codes, meaning all three now serve the same region.
Area code 623 serves Avondale and the surrounding western Phoenix metropolitan area in Arizona. The area code launched on March 1, 1999 as part of a three-way split of the original area code 602 to accommodate rapid population growth and increasing telephone number demand. This guide covers area code 623's geographic coverage, which cities use 623 phone numbers, dialing formats, time zone information, and best practices.
Where is Area Code 623? Geographic Coverage Map
Area code 623 primarily serves the western Phoenix metropolitan area. Avondale is the primary city, but 623 extends to several other major cities and neighborhoods throughout the West Valley.
As of 2023-2024, the 623 region serves an estimated population of over 1 million residents across the West Valley. The area has experienced substantial growth, with cities like Surprise growing from 30,848 in 2000 to over 149,000 by 2023, representing nearly 400% growth in two decades (Data USA - Surprise).
What Cities Are in Area Code 623?
Area code 623 covers these major cities and towns in Arizona's West Valley:
How to Dial 623 Area Code Numbers
Use the correct dialing format to ensure your calls connect successfully.
Why Does 623 Area Code Require 10-Digit Dialing?
The Arizona Corporation Commission ordered 10-digit dialing as part of a boundary elimination overlay implemented in 2023. This decision was driven by two factors:
By eliminating boundaries between 602, 480, and 623, the Commission created a single overlay complex serving 23.4 million potential numbers across the Phoenix metro area.
Standard Dialing Formats
Telecommunications and Regulatory Background: The NANP and Area Code 623
Area code 623 operates under the NANP (North American Numbering Plan), a standardized numbering system established in 1947 that governs telephone numbering across the United States, Canada, and parts of the Caribbean. The NANP ensures consistent call routing through standardized 10-digit numbering (3-digit area code + 7-digit local number).
The North American Numbering Plan Administrator (NANPA) tracks telephone number consumption and recommends new area codes when existing codes approach exhaustion. For Arizona, NANPA convened an industry meeting on April 28, 2021, to address the projected Q1 2024 exhaustion of area code 480 (Arizona Corporation Commission).
Rate Centers and Local Calling
The Phoenix metropolitan area operates as a single rate center – a geographic area used to determine local calling boundaries and billing. Despite having three area codes (602, 480, and 623), the entire Phoenix metro functions as one rate center, meaning calls between these area codes are local calls with no long-distance charges (Wikipedia - Area codes 602, 480, and 623).
This makes Phoenix one of the largest toll-free local calling areas in the United States. A call from Avondale (623) to Scottsdale (480) or central Phoenix (602) is a local call, even though different area codes are involved.
Historical Context and the 2023 Overlay
1947: Area code 602 assigned to cover the entire state of Arizona as one of the original 86 area codes (Wikipedia - Area codes 602, 480, and 623).
March 19, 1995: Area code 520 introduced for all of Arizona outside metro Phoenix, with mandatory dialing phased in through December 31, 1996.
March 1, 1999: Three-way split of 602 created area codes 480 (East Valley) and 623 (West Valley), while 602 retained central Phoenix. The split was approved December 18, 1998, by the Arizona Corporation Commission.
November 2, 2021: Arizona Corporation Commission issued Decision No. 78311 ordering a boundary elimination overlay for 480, 602, and 623 (Arizona Corporation Commission).
February 11, 2023: Permissive 10-digit dialing period began for 602 and 623 area codes. Calls completed whether 7 or 10 digits were dialed.
August 12, 2023: Mandatory 10-digit dialing took effect. Seven-digit calls no longer complete; callers hear a recording instructing them to redial with area code.
September 12, 2023: Official in-service date of the boundary elimination overlay, making all three area codes (480, 602, 623) available throughout the entire Phoenix metropolitan area.
Best Practices for Using Area Code 623
For All Users
For Businesses
Regulatory Compliance
Troubleshooting and Common Issues
Call Fails to Connect
Symptom: You hear a recording stating "Your call cannot be completed as dialed" or similar message.
Cause: You likely dialed only 7 digits for a local call. Since August 12, 2023, 10-digit dialing is mandatory.
Solution: Hang up and redial using the full 10-digit number: area code + 7-digit number (623-555-0123).
Stored Contacts Don't Work
Symptom: Calls to saved contacts fail, especially numbers saved before August 2023.
Cause: Contacts may be stored without area codes, relying on old 7-digit dialing.
Solution: Edit all local contacts to include the full area code. On smartphones, ensure numbers are saved in full format (623-555-0123) or with +1 country code (+16235550123).
Business Phone System Issues
Symptom: Your office phone system can't complete local calls, or auto-dialers fail.
Cause: Legacy PBX systems, alarm systems, or fax machines may require reprogramming for 10-digit dialing.
Solution: Contact your telecommunications vendor or IT department to update system dialing rules. Most systems have settings to force 10-digit local dialing.
Confusion About Which Area Code to Use
Symptom: Uncertainty about whether to use 602, 480, or 623 for a Phoenix-area call.
Cause: The boundary elimination overlay means all three codes serve the same region.
Solution: Use the area code already assigned to the number you're calling. The overlay doesn't change existing numbers – it only allows new numbers in any of the three codes to be assigned anywhere in the metro area.
Unexpected Long-Distance Charges
Symptom: Charges appear for calls you thought were local.
Cause: Your calling plan may have restrictions, or you called outside the Phoenix rate center (e.g., to Tucson 520, Flagstaff 928).
Solution: Review your bill and contact your carrier. By law, calls that were local before the overlay remain local – rates cannot increase due to the overlay (Arizona Corporation Commission).
Getting Help
Frequently Asked Questions About Area Code 623
What cities are covered by area code 623 in Arizona?
Area code 623 primarily covers cities in the western Phoenix metropolitan area, including Avondale, Glendale, Peoria, Surprise, Sun City, Sun City West, Buckeye, Goodyear, El Mirage, Litchfield Park, Tolleson, and Youngtown. The area code also covers portions of west Phoenix and unincorporated areas in Maricopa County and parts of Yavapai County.
When did area code 623 go into service?
Area code 623 went into service on March 1, 1999 (allareacodes.com). It was created as part of a three-way split from area code 602 to accommodate the growing population and increasing demand for phone numbers in the Phoenix metropolitan area. The Arizona Corporation Commission approved the split on December 18, 1998, creating both 623 (West Valley) and 480 (East Valley) while 602 retained central Phoenix (Wikipedia).
What is the difference between 623, 602, and 480 area codes?
Historically (1999-2023), 623 served the western Phoenix area (Avondale, Glendale, Peoria, Surprise, Sun City, Buckeye), 602 served central Phoenix, and 480 served the eastern Phoenix area (Scottsdale, Tempe, Mesa, Chandler). However, effective September 12, 2023, these geographic boundaries were eliminated through a boundary elimination overlay (Arizona Corporation Commission Decision No. 78311). All three area codes now serve the same geographic region covering the entire Phoenix metropolitan area, with mandatory 10-digit dialing for all local calls.
Do I need to dial 10 digits for local calls in area code 623?
Yes, 10-digit dialing is mandatory for all local calls within area code 623 and throughout the Phoenix metropolitan area. As of August 12, 2023, dial the full 10-digit number (area code + 7-digit phone number) for all local calls, regardless of whether you're calling within the same area code or to a different area code in the overlay region.
Can I still get a new 623 phone number?
Yes, you can still obtain new phone numbers with the 623 area code. When the 2023 overlay was implemented, area code 623 had 299 assigned central office codes with hundreds more available – significantly more capacity than 602 and 480, which each had over 700 assigned codes (Arizona Corporation Commission). The overlay system now allows new numbers to be issued in any of the three area codes (623, 602, or 480) throughout the Phoenix metropolitan area, regardless of specific location within the metro.
What time zone is area code 623?
Area code 623 is in the Mountain Standard Time (MST) zone. Arizona does not observe Daylight Saving Time (DST), so the time remains MST year-round. This means during summer months when other states are on Daylight Saving Time, Arizona is effectively on Pacific Daylight Time (PDT), while during winter months it aligns with Mountain Standard Time.
How do I dial a 623 number from outside Arizona?
To dial a 623 number from outside Arizona but within North America, dial 1 + 623 + the 7-digit phone number (1-623-XXX-XXXX). For international calls to a 623 number, dial your country's international access code (e.g., 011 from most countries, or 00 from many others), followed by 1 (the country code for the United States), then 623 and the 7-digit number.
Is area code 623 toll-free?
No, area code 623 is not a toll-free area code. It is a standard geographic area code for the western Phoenix metropolitan area. Toll-free area codes in North America include 800, 888, 877, 866, 855, 844, and 833. Calls to 623 numbers may incur long-distance charges depending on your calling plan and location.
Conclusion: Area Code 623 Essentials
Area code 623 is essential for anyone living, working, or communicating in the Phoenix metropolitan area. Since the September 2023 boundary elimination overlay, 623 serves the entire metro alongside 602 and 480, supporting over 4.7 million residents across Maricopa County.
Key Takeaways:
Additional Resources:
For Businesses & Developers:
If you're building SMS/voice applications or need programmatic access to 623 area code phone numbers, ensure your platform supports E.164 phone number formatting and understand the Phoenix metro's single rate center structure. For high-volume messaging campaigns, consult our guides on 10DLC registration and SMS delivery best practices.