Who Assigns Area Codes?
The North American Numbering Plan Administrator (NANPA) manages area code assignments in the US. NANPA operates under the authority of the Federal Communications Commission (FCC), which sets the overall numbering policy.
When an area code needs relief, the process typically works like this:
- A telecommunications carrier petitions NANPA for relief
- NANPA evaluates the numbering resources in the affected area
- NANPA proposes a relief plan (split or overlay)
- State public utility commissions review and approve
- The new code is activated on a specific date
When Are New Area Codes Needed?
New area codes are created when the existing numbering resources in a region are projected to run out. The key indicators:
- High utilization — when 80-90%+ of available prefixes are assigned
- Growth projections — population or business growth driving demand
- Numbering conservation — even with conservation efforts, some areas exhaust
Our data shows that 158 US area codes now exceed 90% utilization, indicating they are approaching exhaustion.
See the full exhaustion rankings →Relief Methods: Split vs Overlay
There are two ways to add numbering capacity to a region:
Geographic Split
The existing area code's territory is divided. Some customers keep the original code, others get a new one. This was the dominant method through the 1990s.
Example: 201 split into 201 + 908 (1990)
Overlay
A new area code is added to the same geographic region. All customers keep their existing numbers. This requires 10-digit dialing. Since 2010, overlays are the sole relief method.
Example: 408 overlaid by 669 (2012)
The Assignment Process
Once relief is approved, NANPA follows a structured process:
- Code selection — NANPA selects an available 3-digit code from the remaining pool
- Implementation planning — carriers update their systems for the new code
- Permissive dialing period — typically 6-12 months where both 7 and 10 digits work
- Mandatory dialing — 10-digit dialing becomes required
The entire process from petition to activation typically takes 18-24 months.
Reserved Codes
NANPA has assigned area codes in advance of actual need. These codes are reserved but not yet in service — no prefixes have been distributed.
Our database tracks reserved codes that have been assigned but are waiting for activation dates. When a code is activated, it will appear in our Statistics dashboard alongside its prefix utilization data.