Relief Plan
NANP · also called area code relief, NPA relief
The process of adding numbering capacity to an area code approaching exhaustion — usually an overlay, historically a split.
Area-code relief is the process by which numbering capacity is added when an NPA approaches exhaustion. NANPA identifies codes needing relief, the industry and the state regulator select a method, and a planning letter announces the decision with permissive- and mandatory-dialing dates.
The two methods are the overlay (add a new code over the same geography; no one renumbers) and the split (divide the geography; part renumbers). Overlays dominate today.
Relief does not mean a code is "out of numbers" today. It is planning that begins well before actual exhaustion, based on forecasts — and the projected exhaust date is an estimate, not a deadline.
NumberResearch tracks every current relief decision with its dialing dates. See the Relief Tracker ↗.