Area code 423
Area code 423 serves Chattanooga and nearby parts of Tennessee, including Knoxville, Johnson City and Kingsport. It is on Eastern Time, which observes daylight saving time.
Area code 423 at a glance
| State | Tennessee (TN) |
| Main city | Chattanooga |
| Time zone | Eastern Time |
| UTC offset | UTC−5 in winter, UTC−4 in summer |
| Daylight saving time | Yes |
Cities in 423
- Chattanooga
- Knoxville
- Johnson City
- Kingsport
An area code shows where a number was first assigned. Mobile numbers keep their area code when people move, so the person you’re calling may be somewhere else.
When you can call a 423 number
Federal telemarketing rules under the TCPA allow sales calls between 8 AM and 9 PM in the called person’s local time. Here is that window for a 423 number, shown in your own time zone.
General information, not legal advice. Some states add rules for Sundays, holidays or the number of calls. See our calling hours guide.
| If you’re on | You can call 423 between |
|---|---|
| Eastern | 8:00 AM to 9:00 PM |
| Central | 7:00 AM to 8:00 PM |
| Mountain | 6:00 AM to 7:00 PM |
| Arizona | 5:00 AM to 6:00 PM |
| Pacific | 5:00 AM to 6:00 PM |
See the time in 423 without leaving your CRM
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Other area codes in Tennessee
Questions about 423
What time zone is area code 423?
Area code 423 is on Eastern Time. It observes daylight saving time.
Where is area code 423?
Area code 423 is in Tennessee. Its main city is Chattanooga, and it also covers Knoxville, Johnson City and Kingsport.
What are the legal hours to call a 423 number?
Under the federal TCPA, sales calls are allowed from 8 AM to 9 PM in the called person’s local time. Personal and informational calls are not limited by these hours.