A Proposal for Long-Term Expansion of the North American Numbering Plan (NANP) to 11 Digits

The North American Numbering Plan (NANP) is projected to exhaust available telephone numbering resources within the coming decades under current allocation and utilization trends. Existing mitigation strategies, including area code overlays and number pooling, extend the usable life of the NANP but introduce increasing operational complexity and user confusion. This document proposes a long-term, uniform expansion of NANP telephone numbers from 10 to 11 digits through extension of the area code or Numbering Plan Area (NPA) from 3 to 4 digits. The proposal emphasizes backward compatibility, fixed-length numbering, and a multi-phase transition strategy designed to minimize disruption. This document is intended to stimulate discussion and does not represent the position of any standards body or regulatory authority.