US Phone Number Format - A Guidelines to Phone Numbers In the US

usa phone number format

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Dialing the United States phone numbers looks straightforward, but many times calls may fail. This often happens when you do not know the correct US phone number format.  Imagine trying to reach a friend or a business partner and constantly getting error messages - it’s all too common.

Knowing the right dialing process is important to reach the intended recipient without unnecessary delays or errors. In this article, we’ll explore the structure of US phone numbers and provide tips to avoid common mistakes. 

Understanding the US Phone Number Components

US phone numbers consist of an area code, an exchange code, and a subscriber number. All these components have a specific role in guiding your call to the right destination in the US.

Area Code: The area code is the first part of a US phone number and typically consists of three digits. It identifies the specific geographic region of the number you are dialing. For instance, Virginia area code 703 covers the Arlington region, while 804 covers the Richmond area in the Virginia state.

Exchange Code or Central Office Code: After the area code, there’s the exchange code. This three-digit number further narrows down the location within the larger area code region. They direct your calls to the appropriate local network.

Subscriber Number: The subscriber number is the final part of the US phone number structure. This is a 4-digit unique number assigned to a specific line within the exchange. This number ultimately directs your call to the exact receiver.

US Phone Number Format For Local Calls

To make local calls, the US number structure consists of the area code and 7-digit phone number of the recipient.


Here’s how to call the US from within the US:


Step 1: Dial the three-digit area code of the region you’re calling.


Step 2: Dial the 7-digit phone number (exchange code+subscriber number) of the person you’re calling.


(Note: You’ll need to ‘1’ before the area code to make local calls in areas that have implemented ten-digit dialing. For more information on ten-digit dialing, check the ) Federal Communications Commission (FCC) guidelines.


Example of Format for US Phone Number for Local Calls 

Landline Number: 703-555-5678 or 1-703-555-567

  • 703 - Area code
  • 555 - Exchange code
  • 5678 - Subscriber’s landline number


Mobile Number: 212-555-6789 or 1-212-555-6789

  • 212 - Area code
  • 555 - Exchange code
  • 6789 - Subscriber’s mobile number


Toll-free Number: 800-555-1234 or 1-800-555-1234

  • 800 - Toll-free number prefix
  • 555 - Exchange code
  • 1234 - Subscriber number

US Phone Number Format for International Calls

When calling the US from abroad, the US phone number structure includes the international access code, the US country code (1), followed by the area code and the seven-digit number.

Here’s how to call the US from Abroad:

Step 1: Dial the international access code (exit code) of your country. This code varies from country to country. For example, it's ‘011’ for the UK and ‘00’ for France.

Step 2: Enter the US country code, which is ‘1’.

Step 3: Enter the three-digit area code for the region you are calling.

Step 4: Finally, enter the seven-digit phone number of the person you’re trying to reach.

Example of Format for US Phone Number for International Calls 

Landline Number: 00-1-703-555-1234

  • 00 - Exit code (when calling from UK)
  • 1 - US country code
  • 703 - Area code
  • 555 - Exchange code
  • 1234 - Subscriber’s landline number


Mobile Number: 00-1-212-555-4567

  • 00 - Exit code (when calling from UK)
  • 1 - US country code
  • 703 - Area code
  • 555 - Exchange code
  • 4567 - Subscriber’s mobile number

Toll-free Number: 00-1-800-555-3456

  • 00 - Exit code (when calling from UK)
  • 1 - US country code
  • 800 - Toll-free number prefix
  • 555 - Exchange code
  • 3456 - Subscriber number


Things to Consider When Calling to The US

When calling the US, several factors can affect the success and efficiency of your call. These elements can significantly impact the success and efficiency of your call. Here are some important aspects to keep in mind.

Time Zones

The US follows multiple time zones, from Eastern Time (ET), Pacific Time (PT),  Alaska Time, and Hawaii-Aleutian Time Zones. So, time may differ from city to city in the US. For example, if it’s 9 AM in New York (ET), it’s only 6 AM in Los Angeles (PT). When you’re calling someone, you wouldn’t want it to be an appropriate time for the receiver. Knowing the time difference is crucial to avoid calling too early or too late.

US Area Codes

Area codes are important in the US phone number format as they designate specific geographic regions. They help route calls to the correct location within the country. The US has over 300 area codes. You must familiarize yourself with the area codes to make sure that your call is directed to your intended region in the country. Here’s the list of the top area codes in the United States:

Area Code


     Area Code



New York City, NY


Los Angeles, CA


Chicago, IL


maimi, FL


Las Vegas, NV


Boston, MA


San Francisco, CA


Atlanta, GA


Seattle, WA


Northern Virginia, VA


Washington, DC


Chicago, IL


Dallas, TX


Atlanta, GA


Houston, TX


San Fernando Valley, CA


Phoenix, AZ


Orlando, FL


Denver, CO


San Antonio, TX


Portland, OR


Austin, TX


Honolulu, HI


San Diego, CA


Raleigh, NC


Brooklyn, NY

Call Cost

The phone call cost, especially when calling internationally, is typically very high. It can be significantly expensive, especially when you need to make the calls frequently. However, you can reduce the cost using VoIP numbers. These numbers use the internet to make calls, bypassing the traditional phone networks and their hefty fees.

What are the common mistakes when calling the US, and how can we avoid them?

While calling the US, you may fail to connect due to various mistakes. The common errors include dialing the wrong format, not verifying the number, and not testing the connection.

Dialing the Wrong Format: This is one of the most common mistakes. Many forget to include international access codes when calling internationally. To avoid this, always remember the international dialing format for the US phone number - the country code  (e.g., 00 or +), followed by 1, and then the area code and receiver’s number.

Not Verifying the Number: Often, the call fails when you do not verify the phone number before dialing. For instance, incorrectly identifying the area code or exchange code can lead to failed call attempts. So, double-check the number for accuracy and make sure you have all the correct digits.

Not Testing Your Connection: When there’s a poor network connection in your area, you will not be able to make a call. It leads to dropped calls or poor audio quality. So, check your network signal before making calls. If the signal is weak, try to call from a different location. 


You must follow the US phone number format accurately to successfully connect to individuals or businesses in the United States. To call locally within the US, you'll need to dial the area code followed by the seven-digit phone number. For international calls, you'll dial the exit code of your country, the US country code (1), the area code, and then the seven-digit number.

Sometimes, even if you dial the correct format, you may face issues in connection. Most of the time, this is due to the network problems. Using Calilio's virtual phone numbers can help you avoid these issues. Our virtual numbers with advanced technology ensure no issues in connecting the US or any part of the world.

Frequently Asked Questions

What is the format for a +1 phone number?

+1 is the country code for the United States. The format for the +1 number is ‘+1 (area code) (exchange code) (subscriber number). For instance, the number might look like this - ‘+1 212 555 4567’.

How many digits is an American phone number?

An American phone number typically consists of 10 digits. This includes a three-digit area code, a three-digit exchange code, and a four-digit subscriber number.

How do you format a US phone number?

To format a US phone number, dial area code + exchange code + subscriber number. For instance, to 212-555-6789. Here, 212 represents the area code, 555 represents the exchange code, and 6789 represents the subscriber number of the individual or business within the US.

Is US country code 001 or 1?

The US country code is 1. When dialing internationally to the US, you will typically use the exit code for your country followed by 1. For example, you would dial 00 1 from the UK, then the area code and phone number.

How to find the area code of a specific city in the US?

To find the area code of a specific city in the US, you can use online tools and directories that list area codes by city. Additionally, you can refer to the Federal Communications Commission (FCC) website for accurate information.

How do I know my country's exit code so I can dial it to the US?

Your country's exit code can usually be found through a quick online search or by checking with your phone service provider. Common exit codes include 011 for the US and Canada, 00 for many European countries, and 0011 for Australia.

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