Area code 423 – Tennessee
423 has served Tennessee since 1995, split from 615. 764 of its 786 number blocks are allocated – about 97% full. No carrier dominates: AT&T 28.1%, Lumen / CenturyLink 16.1%, Other CLEC / VoIP 15.2%. It shares its geography with overlay codes 729, so local calls take all ten digits. It is also among the most imitated codes in spam calls: 1,346 FTC complaints named a 423 caller ID in the 33 days to 30 October 2026, ranking 12th of 422 ranked codes.
Who holds 423 number blocks
Share of the 764 assigned NXX blocks (97.2% of the 786 possible), across 55 carriers. This is share of number blocks, not of subscribers.
- AT&T28.1%
- Lumen16.1%
- Other CLEC / VoIP11.9%
- Verizon11%
- T-Mobile9.7%
- Onvoy7.1%
- Windstream4.3%
- Bandwidth3.9%
- Comcast2.2%
- Charter1.8%
- Spok0.9%
- Telnyx0.9%
- Brightspeed0.8%
- Dish0.4%
- Vonage0.3%
- Twilio0.3%
- Peerless0.3%
Spam complaints naming 423
FTC Do Not Call complaints where the caller ID was a 423 number, 28 Sep – 30 Oct 2026 (33 days). Caller IDs on spam calls are frequently spoofed, so these are complaints about the code, not calls proven to originate in it.
Rate centers in 423
NANPA allocates number blocks to rate centers and records their names abbreviated to ten characters, so these are NANPA's codes rather than place names – CHAMPAURBN is Champaign-Urbana, NWYRCYZN01 is a New York City zone. We show them unchanged instead of guessing at the full names. Showing the largest 5 of 75.
Timeline
- 1995 423 goes into service, split from or overlaid on 615.
More about 423
Separate pages for the questions that need their own answer: what time it is there, what the complaint data says, who holds the number blocks, and how the code compares with the one it shares its area with.
Frequently asked about 423
What state is area code 423?
Tennessee. It covers the same area as 423/729.
Can I still get a 423 number?
Only from recycled stock. 764 of the 786 available blocks are already allocated, so new numbers in the area normally come from the overlay codes (423/729).
Is a call from 423 a scam?
423 is one of the most complained-about codes in the country – 1,346 FTC complaints in the 33 days to 30 October 2026, 12th of 422 ranked codes. Most of those calls are spoofed: the caller fakes a local-looking number because it gets answered more often. Look up the specific number rather than judging by the code.
Which carrier owns 423 numbers?
AT&T holds the largest share of assigned number blocks at 28.1%. The rest is spread across 3 other carriers. This is share of number blocks, not of subscribers – people keep their numbers when they switch carriers.
Do I need to dial 10 digits in 423?
Yes – ten digits for local calls in 423, because it shares its area with another code.
Sources and verification
- NANPA – NPA Database (npa_report.csv), file date 11/01/2026, retrieved Nov 1, 2026
- NANPA – CO Code Assignment Records, All States (utilized), file updated 11/01/2026, retrieved Nov 1, 2026
- FTC – Do Not Call Reported Calls Data, 25 daily files 28 Sep – 30 Oct 2026, retrieved Nov 1, 2026
NANPA dialing note for this code: “10D”. Reviewed by the data desk. Spotted an error? Request a correction.