The Data Behind Exhaustion
Our analysis of 361 US area codes with NANPA utilization data reveals that 158 codes (44%) now exceed 90% utilization — meaning more than 9 of every 10 available phone numbers have been assigned.
But exhaustion is not evenly distributed. Some states face immediate pressure while others have significant headroom. Here's what the data shows.
Why Some States Exhaust Faster
Population Density
Denser states require more phone numbers per square mile. New Jersey (5,984 people/sq mi) exhausts faster than Montana (7.5 people/sq mi) — not because NJ has more people, but because numbers are concentrated in a smaller area.
Number of Area Codes
States with fewer area codes have less capacity. Montana has just 1 code serving the entire state, while California has 36. A single-code state has no ability to absorb demand spikes.
Economic Activity
Business density drives number consumption. Each business phone line, VoIP account, and fax machine consumes a number. States with concentrated business districts exhaust faster.
Overlay vs Split History
States that relied on splits (creating more, smaller codes) may have different exhaustion patterns than those that used overlays (sharing the same geographic area).
What Our Analysis Reveals
| State | Avg Utilization | Total Codes | Above 90% |
|---|---|---|---|
| MT | 94.2% | 1 | 1 |
| NH | 94.0% | 1 | 1 |
| SD | 93.1% | 1 | 1 |
| ND | 92.9% | 1 | 1 |
| ME | 92.8% | 1 | 1 |
| HI | 86.4% | 1 | 0 |
| AK | 82.1% | 1 | 0 |
| DE | 81.9% | 1 | 0 |
| WV | 80.0% | 2 | 1 |
| AZ | 79.2% | 5 | 2 |
| GA | 78.5% | 10 | 6 |
| MD | 77.5% | 6 | 4 |
| NM | 75.3% | 2 | 0 |
| UT | 73.8% | 3 | 1 |
| WA | 73.5% | 6 | 3 |
Key finding: The highest average utilization rates are in small states with few area codes. Montana (94.2%), New Hampshire (94.0%), and South Dakota (93.1%) all have just 1 area code each — leaving no capacity buffer.
The Utilization Spectrum
Utilization ranges from near-zero (newly created codes) to over 99% (codes approaching exhaustion). The distribution is not uniform — it follows a pattern where:
- Single-code states tend toward high utilization (80-95%)
- Multi-code states show wider variation (40-90%)
- Recently split states often have one high-utilization legacy code and one lower-utilization new code
Methodology
This analysis is based on NANPA Prefix Utilization Report data for361 US area codes. Utilization is calculated as the percentage of assigned prefixes out of total available prefixes (NXX codes). Population density uses Census ACS 5-year estimates. All data is sourced from official NANPA and Census Bureau publications.
Data as of August 24, 2026.
See full data sources →