US local DID
A standard 10-digit number with a chosen area code. Inbound calls can be delivered to SIP, a cloud PBX, or a contact center.
View US numbers → Resources · US Numbering Guide
US Phone Number Format: Area Codes, Dialing Rules and Number Types
A practical, source-backed guide to US phone numbers: the 10-digit structure, how to dial from abroad, the area codes used in major metros, and what to check before choosing a US business number.
10digits in a US number
Three-digit area code, three-digit central office code, four-digit line number.
+1country code
Use +1 when calling from outside the North American Numbering Plan.
2–9first digit of an area code
US area codes never begin with 0 or 1.
10digits to dial
Required in overlay areas and most major metro markets.
Number structure
What is the structure of a US phone number?
A US phone number is made up of 10 digits: a three-digit area code (NPA), a three-digit central office code (NXX), and a four-digit line number. When dialing from outside the North American Numbering Plan, add the country code +1[1].
| Part | Digits | Example | What it identifies |
|---|---|---|---|
| Country code | 1 | +1 | The North American Numbering Plan; used for international calls |
| Area code (NPA) | 3 | 212 | The geographic numbering plan area |
| Central office code (NXX) | 3 | 555 | The local exchange that serves the line |
| Line number | 4 | 0123 | The individual subscriber line |
In international format, (212) 555-0123 becomes +1 212 555 0123 or +12125550123. Area codes and exchange codes cannot begin with 0 or 1[1][2], and the range 555-0100 to 555-0199 is reserved for fictional use.
Common formats
How are US phone numbers written?
Formatting is for readability. The network routes the call using the digits only, so the same number can appear in several accepted formats.
| Format | Example | Typical use |
|---|---|---|
| Parentheses | (212) 555-0123 | Business cards, invoices, and directories |
| Hyphens | 212-555-0123 | General writing and online forms |
| Dots | 212.555.0123 | Some software and CRM fields |
| International | +1 212 555 0123 | Calls from outside the United States |
| E.164 | +12125550123 | APIs, databases, and telephony systems |
| Plain digits | 2125550123 | Data storage and validation |
Use E.164 (+1 followed by 10 digits, no spaces or punctuation) when storing a number in a CRM, API, or call-routing system. It removes ambiguity about the country and area code.
International dialing
How do you dial a US number from another country?
Dial your country's international access code, then 1, then the 10-digit US number. On a mobile phone, a leading + usually replaces the access code, so +1 works in most countries[3].
| Calling from | Access code | Example |
|---|---|---|
| United Kingdom | 00 | 00 1 212 555 0123 |
| China | 00 | 00 1 212 555 0123 |
| Australia | 0011 | 0011 1 212 555 0123 |
| Japan | 010 | 010 1 212 555 0123 |
| Germany | 00 | 00 1 212 555 0123 |
Common dialing mistakes
- Adding a leading zero. US numbers do not use a trunk prefix; 0 1 212… will not connect.
- Omitting +1. Outside the NANP, the area code alone is not enough.
- Dialing 011 from abroad. 011 is the exit code used when calling out of the United States, not an entry code for calling in.
- Dropping digits. A US number always needs all 10 digits after the country code.
Area codes
How do US area codes work?
An area code is the first three digits of a US number. It identifies the numbering plan area that the call is routed to. A single city or region can have several area codes, and the same area code can cover very different-sized territories[1].
Area code rules
- An area code has three digits and never starts with 0 or 1[1][2].
- Geographic area codes cover states, cities, and regions; non-geographic codes include toll-free (800, 833, 844, 855, 866, 877, 888) and premium (900) numbers.
- Overlay: a new area code is added to the same area. Existing numbers keep their code, and callers must dial 10 digits[3].
- Split: an area is divided and some numbers receive a new area code.
- Assignments and dialing rules change over time, so verify current coverage before publishing a number or printing it on materials.
Area codes for major US metros
The table below lists common area codes for major markets. Overlay codes share the same geography; the list is not a complete national directory.
| Metro | Common area codes | Notes |
|---|---|---|
| New York City | 212, 332, 646, 917 | Manhattan |
| New York City | 718, 347, 929 | Brooklyn, Queens, Bronx, Staten Island |
| Los Angeles | 213, 323, 310, 424, 626, 661, 747, 818 | City and Los Angeles County |
| Chicago | 312, 773, 872 | Downtown and surrounding neighborhoods |
| Houston | 281, 346, 713, 832 | Greater Houston |
| Dallas–Fort Worth | 214, 469, 945, 972 | Dallas side |
| Dallas–Fort Worth | 682, 817 | Fort Worth side |
| Washington, DC | 202, 771 | District of Columbia |
| San Francisco | 415, 628 | City and county |
| Miami | 305, 786 | Miami-Dade |
| Boston | 617, 857 | City and nearby communities |
| Seattle | 206, 425 | Seattle and the Eastside |
| Phoenix | 480, 602, 623, 928 | Greater Phoenix |
| Atlanta | 404, 470, 678, 770 | City and metro |
For a complete and current list, use the North American Numbering Plan Administration (NANPA) area code resources linked in the sources section. You can also download the normalized area code dataset used for the table above.
Open dataset
US area code coverage dataset
A normalized, machine-readable snapshot of US area codes mapped to states and cities. Use it for research, lookups, and building your own tools.
305area codes
One row per NPA, with state and city coverage.
51states + DC
All 50 states and the District of Columbia.
2,720NPA-city pairs
Aggregated from a public-domain NANPA-derived source.
CC BY 4.0license
Free to reuse with attribution to Vanttel.
Download CSVSpreadsheet-friendly, one NPA per rowDownload JSONRows plus metadata for applicationsSHA-256 checksumsVerify the files you downloaded
| NPA | State | Primary city | Mapped cities | Origin |
|---|---|---|---|---|
| 212 | New York | New York City | 1 | Snapshot |
| 332 | New York | New York City | 1 | Curated overlay |
| 771 | District of Columbia | Washington | 1 | Curated overlay |
| 305 | Florida | Aventura | 26 | Snapshot |
| 312 | Illinois | West Chicago | 1 | Snapshot |
| 404 | Georgia | Atlanta | 7 | Snapshot |
| 415 | California | Novato | 4 | Snapshot |
| 713 | Texas | Alvin | 18 | Snapshot |
Coverage note: Includes area codes mapped to at least one city in the source snapshot plus curated overlays for the metros listed on this page. Newer overlays may be missing; confirm current assignments with NANPA before relying on a code. Source: Area-Code-Geolocation-Database (Area-Code-Geolocation-Database (ravisorg), compiled from public NANPA data), retrieved 2026-10-21. The normalized compilation is published under CC BY 4.0.
Cite this dataset
Vanttel. (October 21, 2026). US Area Code City Coverage Dataset (Version 2026-10). https://www.vanttel.com/data/us-area-code-coverage.csv. CC BY 4.0.
Business numbers
What types of US numbers can a business use?
The right number type depends on whether you need a local presence, a free-to-call sales line, a mobile identity, or routing into an existing phone system.
US toll-free
An 800, 833, 844, 855, 866, 877, or 888 number. Eligible callers do not pay the call charge; the business pays applicable fees.
Explore toll-free →Virtual mobile number
A mobile-format number for voice and messaging. SMS and voice features depend on the market, carrier, and number type.
See mobile numbers →Cloud PBX
Route US numbers to extensions, IVR menus, call queues, or distributed agents without building a local phone system.
Explore Cloud PBX →Number types and codes
What toll-free and special numbers exist in the US?
Toll-free codes are used for business inbound lines. Short service codes are reserved for emergency, directory, relay, and government services[1].
| Prefix | Type | Who pays |
|---|---|---|
| 800, 833, 844, 855, 866, 877, 888 | Toll-free | The business pays; eligible callers do not |
| 900 | Premium | The caller pays a per-minute or per-call charge |
Common short service codes
| Code | Service | Notes |
|---|---|---|
| 911 | Emergency services | Police, fire, and medical emergencies |
| 988 | Suicide & Crisis Lifeline | Call or text 988 in the United States[4] |
| 411 | Directory assistance | May incur a fee depending on the carrier |
| 511 | Traffic and travel information | Availability varies by state |
| 611 | Carrier customer service | Reaches the carrier of the line |
| 711 | Telecommunications relay service | For callers who are deaf or hard of hearing |
| 811 | Utility locate service | Call before digging |
| 211 | Community services | Availability varies by area |
| 311 | Local government services | Availability varies by city |
Mobile and landline
Is there a difference between US mobile and landline numbers?
Not in the number format. Both use the same 10-digit structure, and both can be dialed the same way. After number portability, the prefix does not reliably tell you whether a number is mobile, landline, or VoIP.
- Portability: customers can move a number between carriers while keeping the same area code and line number[2][5].
- Calling: the dialing rules are the same; the difference is in the network and the services attached to the number.
- Messaging: SMS and MMS support depends on the number type, carrier, and provider. A voice number does not automatically support two-way messaging.
- Emergency calling: VoIP and virtual numbers need a registered service address for E911, and the address must be kept current[6].
For business use, decide whether you need voice only or voice plus SMS. Messaging eligibility is reviewed separately from number activation.
Before you buy
What should you check before buying a US business number?
Number availability, documentation, and feature support vary by area code and number type. Confirm these points before you publish the number or route live traffic.
- Confirm the primary use case: sales, support, verification, or internal routing.
- Choose local, toll-free, or mobile based on how customers should reach you.
- Check area code inventory and whether the exact code you want is available.
- Confirm voice and SMS support separately; not every number supports both.
- Plan call routing, business hours, voicemail, and E911 before launch.
- Prepare business verification documents if the number type or market requires them.
Vanttel can confirm availability, documentation, and routing options for your target market. Start with US numbers or contact our team.
FAQ
US phone number FAQ
Short answers to the questions buyers ask most often about US numbers, area codes, and dialing.
Is a US phone number always 10 digits?
Yes. A US number consists of a three-digit area code, a three-digit central office code, and a four-digit line number. When calling from outside the North American Numbering Plan, add the country code +1.
What is the country code for the United States?
The country code is +1. The same code covers the United States, Canada, and other NANP members, so the area code is what identifies the specific region.
Do I need to dial 1 before a US number?
For calls within the NANP, you generally dial 1 followed by the 10-digit number for long-distance calls. In overlay areas and many states, local calls also require all 10 digits. From abroad, dial +1 and the 10-digit number.
Can two area codes cover the same city?
Yes. An overlay area code is assigned to the same geographic area when the existing code runs out of numbers. In overlay areas, callers must dial 10 digits so the network can route the call correctly.
Which area code is 212?
212 is a Manhattan area code in New York City. Manhattan numbers may also use 332, 646, or 917, while the other New York City boroughs use 718, 347, or 929.
Is 555 a real area code?
No. 555 is an exchange code often used in films and sample data. The range 555-0100 through 555-0199 is reserved for fictional use and is not assigned to real subscribers.
Can I choose a US area code for my business number?
Often, yes. Local number providers can offer numbers in specific area codes, subject to inventory and carrier rules. Some area codes are limited or require business verification.
Can I receive SMS on a US phone number?
It depends on the number type and provider. Voice-focused numbers may need SMS enablement, and toll-free messaging usually requires a separate verification process. Confirm messaging support before you buy.
Can a US number be ported to another carrier?
Yes. Local number portability lets customers keep their number when switching carriers. Porting times vary by number type, carrier, and how accurately the records match.
Do I need a US address to get a US number?
Not always. Requirements vary by number type and provider. Some local numbers can be activated with business information, while certain products require additional verification or a local address.
Sources
Sources and how we verify this page
Numbered citations in this guide point to the sources below. We compile the page from primary numbering and regulatory material, and we re-check area code assignments when NANPA publishes updates.
- NANPA — North American Numbering Plan Administration. Area code maps, planning letters, and numbering resources. Accessed October 21, 2026
- eCFR — 47 CFR Part 52 — Numbering. Federal rules for numbering and number portability. Accessed October 21, 2026
- FCC — Ten-Digit Dialing. Consumer guidance on overlay areas and 10-digit dialing. Accessed October 21, 2026
- FCC — 988 Suicide & Crisis Lifeline. Background on the 988 short code. Accessed October 21, 2026
- FCC — Local Number Portability. How numbers are ported between carriers. Accessed October 21, 2026
- FCC — Enhanced 911 (E911). Service address requirements for VoIP and virtual numbers. Accessed October 21, 2026
Cite this page
Vanttel. (2026). US Phone Number Format: Area Codes, Dialing Rules and Number Types. https://www.vanttel.com/us-phone-number
Last verified: October 21, 2026. This page is educational and does not replace confirmation from a carrier or regulator. Area code assignments and dialing rules change; confirm current details with the linked sources.
Next step
Need a US number for your business?
Tell us your target market, call flow, and whether you need voice, SMS, or both. We will confirm availability, documentation, and routing options.