US Phone Number Format: Area Codes and How to Write Them Correctly
2026-08-26 · US Address Generator
Besides the address, the other field US forms love to reject is the phone number. The format is remarkably consistent: three digits for the area code, three for the exchange, four for the line. Get it right and most validation errors disappear.
Standard format and common variants
A US phone number is 10 digits, prefixed by the country code 1:
- Standard: +1 (212) 555-0123
- Common variants: 212-555-0123, (212) 555-0123, +12125550123
- International dialing always uses +1, or the international prefix 011 followed by 1 and the 10-digit number.
What area codes mean
Area codes roughly track geography, though with mobile numbers they increasingly mark where a number was first registered rather than where the person is. Representative cities:
| Area code | City | Note |
|---|---|---|
| 212 / 646 | New York | 212 is the classic Manhattan code |
| 310 / 213 | Los Angeles | 213 covers downtown |
| 415 | San Francisco | Bay Area classic |
| 312 | Chicago | Downtown |
| 305 | Miami | Florida |
| 202 | Washington, DC | The capital |
More codes are searchable in the US area code tool on this site.
Special ranges: 800, 900 and N11
- 800/888/877/866/855/844: toll-free numbers.
- 900: premium-rate, rarely used by individuals.
- N11 short codes: 911 emergency, 411 directory, 311 city services.
Why movies always use 555 numbers
The range 555-0100 through 555-0199 is reserved for fiction and examples and is never assigned to real subscribers. Phone numbers generated on this site follow the same example-style convention: they are for testing and demos, not real users.
Calling the US from abroad
From a mobile, dial +1 followed by the 10-digit number. From a landline, dial the international prefix 011, then 1, then the number. The reverse direction — calling China from the US — is +86 plus the number.
With address and phone sorted, most forms stop complaining. Try a full sample in the generator.