US Phone Number Generator Guide: Formats & Area Codes
Everything QA teams need to know about US national vs E.164 formatting, state mixes, and sample presets.
2025-01-07•Best Practices
US numbering basics
American numbers follow the +1 country code, three-digit area code, and seven-digit subscriber number. National formatting (e.g., (415) 555-0130) differs from the E.164 version (+14155550130).
Pick the right preset
Use the “US QA Test Pack” to blend East/West Coast area codes, or limit prefixes to match specific regions like NYC (212) or Bay Area (415). Keep uniqueness enabled to avoid duplicates inside CRM flows.
Testing ideas
- Validate form masks by toggling between national and E.164 output.
- Feed 10k+ numbers into load tests to stress signup rate limiting.
- Export CSV packs to share with call-center tooling vendors.
Link back to the generator
Bookmark the generator with URL fragments (e.g., #us) so teammates can reopen the same preset and regenerate a clean batch.