Key Findings
The 330 area code (OH) has the highest utilization rate at 98.38%, with 787 of 800 prefixes assigned. When utilization exceeds 95%, NANPA typically begins relief planning — either an overlay or a split — to ensure continued number availability.
Full Rankings
| Rank | Area Code | Utilization |
|---|---|---|
| 1 | 330 | 98.4% |
| 2 | 408 | 98.4% |
| 3 | 213 | 98.3% |
| 4 | 217 | 98.3% |
| 5 | 256 | 98.3% |
| 6 | 267 | 98.3% |
| 7 | 281 | 98.3% |
| 8 | 310 | 98.3% |
| 9 | 317 | 98.3% |
| 10 | 323 | 98.3% |
| 11 | 360 | 98.3% |
| 12 | 407 | 98.3% |
| 13 | 469 | 98.3% |
| 14 | 470 | 98.3% |
| 15 | 484 | 98.3% |
| 16 | 540 | 98.3% |
| 17 | 561 | 98.3% |
| 18 | 573 | 98.3% |
| 19 | 618 | 98.3% |
| 20 | 619 | 98.3% |
| 21 | 702 | 98.3% |
| 22 | 713 | 98.3% |
| 23 | 714 | 98.3% |
| 24 | 740 | 98.3% |
| 25 | 770 | 98.3% |
| 26 | 786 | 98.3% |
| 27 | 805 | 98.3% |
| 28 | 815 | 98.3% |
| 29 | 832 | 98.3% |
| 30 | 847 | 98.3% |
| 31 | 909 | 98.3% |
| 32 | 205 | 98.1% |
| 33 | 208 | 98.1% |
| 34 | 214 | 98.1% |
| 35 | 240 | 98.1% |
| 36 | 248 | 98.1% |
| 37 | 304 | 98.1% |
| 38 | 305 | 98.1% |
| 39 | 312 | 98.1% |
| 40 | 415 | 98.1% |
| 41 | 443 | 98.1% |
| 42 | 510 | 98.1% |
| 43 | 512 | 98.1% |
| 44 | 608 | 98.1% |
| 45 | 678 | 98.1% |
| 46 | 707 | 98.1% |
| 47 | 715 | 98.1% |
| 48 | 720 | 98.1% |
| 49 | 757 | 98.1% |
| 50 | 760 | 98.1% |
Methodology
Data sources: Prefix utilization data from the NANPA NPA Exhaust Analysis report. Relief planning status from the NANPA NPA Relief Planning Reports.
Utilization %: Calculated as (assigned prefixes / total assignable prefixes) × 100. Only prefixes marked as "assigned" in the NANPA database are counted.
Ranking: Area codes are sorted by utilization percentage (descending), with ties broken by total assigned prefixes.
Last updated: August 8, 2026
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