What is the Telephone Code of the United States? Basic Rules for Making Calls to the United States

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You need to know that the international country code for the United States is +1. Calling the USA follows a simple international standard format.

Mastering the correct US country code and dialing format is the first step to ensuring smooth communication with friends, colleagues, or partners in the United States. By following this simple rule, you can easily connect to any US number.

Core Points

• When calling the United States, the country code is “+1”.
• US phone numbers consist of three parts: country code, three-digit area code, and seven-digit local number.
• When using a mobile phone to call the US, entering “+1” directly is more convenient than entering the international access code.
• When making calls within the United States, it is now generally required to dial the full 10-digit number (area code + local number).
• To call internationally from the United States, dial “011” or “+” first, followed by the country code, area code, and local number.

US Country Code and Dialing Format

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To successfully call the United States, you need to understand the structure of its phone numbers and international dialing rules. This set of rules follows the E.164 standard established by the International Telecommunication Union (ITU). This standard ensures a unified format for global phone numbers, making each number unique worldwide. The US telephone system is part of this global plan.

A complete US phone number consists of three parts: country code, area code, and local number. Let’s break them down one by one.

International Access Code and the “+” Sign

When calling from one country to another, you first need to enter an “international access code” or “exit code”. This code tells your telephone service provider that you are making an international long-distance call.

• The international access code for mainland China is 00
• The international access code for the United Kingdom is 00
• The international access code for Mexico is 00

Tip: Using the “+” sign is simpler On modern smartphones, you don’t need to memorize each country’s international access code. Simply long-press the “0” key on the dial pad to enter a “+” sign. This “+” sign is a universally recognized prefix that automatically replaces your local international access code.

Therefore, there are two standard formats for calling the United States:

1. Your local international access code + 1 + area code + local number
2. + + 1 + area code + local number

For example, if you want to call a New York number from mainland China, and the number is (212) 555-1234, you can dial:
00-1-212-5551234

Or, more conveniently using a mobile phone:
+1-212-5551234

US Area Code

After the country code 1, you need to enter a three-digit area code (Area Code). This is part of the US phone code and primarily identifies the geographic region of the phone number.

The US telephone numbering system was originally designed in 1947. At that time, to enable efficient nationwide automatic dialing, AT&T published the “National Numbering Plan”. This plan established 86 numbering plan areas (NPA), each assigned a three-digit area code. This system is the precursor to today’s North American Numbering Plan (NANP), which provides a unique address for every telephone on the continent.

For example, 212 is the area code for Manhattan in New York City, while 310 is the area code for parts of Los Angeles, California.

Local Number

Following the area code is the seven-digit local number (Local Number). These seven digits further pinpoint the call to a specific telephone line. It consists of two parts:

• Exchange Code: The first three digits of the local number. It routes the call to a smaller area or a specific telephone exchange center.
• Subscriber Number: The last four digits of the local number. This is the unique number assigned to an individual or company, ultimately connecting the call to the intended recipient.

Interestingly, the first digit of the exchange code has specific rules—it cannot be 0 or 1, due to technical reasons in early telephone networks.

Overall, the structure of a complete US phone code and number is shown in the table below:

Combining them forms the complete number used when dialing: +1 (212) 555-1234.

Structure of US Phone Numbers

Now that you understand the basic dialing format, let’s take a closer look at how a complete US phone number is structured. You’ll find that whether it’s a mobile or landline, the structure is identical.

All US phone numbers follow a system called the North American Numbering Plan (NANP). This plan ensures each number is unique. A standard US number has a total of 10 digits with a very clear structure:

3-digit area code (Area Code) + 7-digit local number (Local Number)

Introduction to the North American Numbering Plan (NANP)

The North American Numbering Plan was established in 1947 with the goal of unifying the then-chaotic telephone network, allowing people to make long-distance calls directly without operator assistance. This system serves not only the United States but also Canada and several countries and territories in the Caribbean, such as:

• Bahamas
• Jamaica
• Bermuda
• Dominican Republic

These countries and regions all use +1 as their country code and share the same numbering rules.

Meaning of the 3-Digit Area Code

The area code is the first 3 digits of the 10-digit number, used to identify the geographic region of the phone number. For example, 310 represents parts of Los Angeles, and 713 represents Houston.

As the number of telephone users increases, a region’s number resources may be exhausted. At that point, telecommunications authorities use a method called “overlay” to add more numbers.

Simply put, “overlay” means introducing a new area code in the same geographic area. Existing users’ numbers and area codes remain unchanged, while new users receive numbers with the new area code. The only change is that everyone in the area (including existing users) must dial the full 10-digit number (area code + local number) when making local calls.

Additionally, not all area codes are tied to geographic locations. Some special US phone codes are reserved for specific services.

Structure of the 7-Digit Local Number

The 7 digits following the area code are the local number, typically written as NXX-XXXX.

• NXX (Exchange Code): These 3 digits represent a specific telephone exchange center, routing your call to a smaller area.
• XXXX (Subscriber Number): The final 4 digits are the unique line number assigned to a specific residence or company, ultimately connecting you to the recipient.

In the early days of telephony, exchange codes were even associated with letters, using the first two letters of a telephone exchange name plus a digit. With technological advancements, this system evolved into the all-numeric format we use today, enabling automated long-distance dialing.

Differences Between Domestic and International Dialing in the US

After understanding the number structure, you also need to know the differences between dialing within the US and making international calls from the US. These two scenarios have completely different dialing rules.

Making Calls Within the United States

When making calls within the United States, the rules have become very uniform. Nowadays, whether calling locally or long-distance, you generally need to dial the full 10-digit number (area code + 7-digit local number).

This change was primarily to promote the nationwide mental health crisis hotline 988. To make this three-digit number effective across all area codes, the telecommunications system underwent a comprehensive upgrade.

• All local calls, even within the same area code, now require dialing the full 10-digit number.
• This rule applies to all areas that previously only required dialing 7 digits.
• Since October 2021, 10-digit dialing has become mandatory.

Do you need to add “1” before dialing? In the past, you needed to dial “1” before long-distance calls to indicate it was a long-distance call. Nowadays, most mobile phones and service providers no longer require it. However, when calling toll-free numbers (such as those with 800, 888 area codes), it is still recommended to add “1” before the number.

Making International Calls from the United States

When calling other countries from the United States, you need to use a completely different format. You must first enter an “exit code” to tell the telephone network you are making an international call.

The US exit code is 011. On smartphones, you can also use the + sign instead of 011.

The steps for making international calls from the US are as follows:

1. Dial the US exit code 011 (or enter + on a mobile phone).
2. Dial the country code of the destination country (for example, China is 86, the UK is 44).
3. Dial the area code of the destination city (if required, remember to omit the leading “0” in the area code).
4. Dial the local phone number.

For example, to call a Beijing number in China (010) 1234-5678 from the US, you should dial:

011-86-10-12345678 or +86-10-12345678

International long-distance rates vary widely, depending on your service provider, plan, and the country you are calling. Here are some approximate rate references:

Note: Using VoIP (Voice over Internet Protocol) services is usually cheaper than traditional landlines for international calls. It’s best to confirm specific rates with your service provider before calling.

Area Code Lookup for Major Cities

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After understanding the number structure, you may want to know the area codes for some major US cities. The US is vast, with numerous area codes. Below is a list of common area codes for major cities to help you look them up quickly.

Northeast City Area Codes

The Northeast is a densely populated region in the US, so its area code system is relatively complex. A single city often has multiple area codes.

• New York City: 212, 646, 917 (mainly for Manhattan), 718, 347, 929 (for the four boroughs outside Manhattan)
• Boston: 617, 857
• Philadelphia: 215, 267

Why does one city have so many area codes? This is due to the “overlay” scheme mentioned earlier. When an area code’s numbers are nearly exhausted, telecom companies add a new area code in the same region. For example, 212 is the classic area code for Manhattan in New York, but as phone numbers increased, 646 and 917 were later added as supplements.

West Coast City Area Codes

The West Coast is known for its tech hubs and entertainment industry, with high demand for phone numbers.

• Los Angeles: 213 (downtown), 310, 424 (western areas like Santa Monica), 323 (Hollywood), 818 (San Fernando Valley)
• San Francisco: 415, 628
• Seattle: 206

The widespread use of mobile phones has greatly accelerated the consumption of number resources. To address this, overlay area codes have become the most common solution. For example, western Washington state originally planned to introduce the new area code 564 in 2001, but through number pool optimization and other technical measures, this was delayed until 2017 when it was officially implemented.

Southern and Midwestern City Area Codes

The southern and midwestern regions of the US also have many important cities with distinct area codes.

• Chicago: 312 (downtown), 773 (areas outside downtown)
• Houston: 713, 281, 832
• Detroit: 313
• Atlanta: 404, 678, 470

How to Look Up a Specific Area Code

If you want to find the area code for a specific city or region, the fastest way is to use online tools. You don’t need to memorize all area codes.

1. Use a search engine: Simply search “city name + area code” on Google or Baidu, and you’ll usually get the answer immediately.
2. Professional lookup websites: You can visit specialized area code lookup websites that provide more detailed information.
   • AreaCode.org: A comprehensive area code directory where you can find lists of cities covered by area codes and maps.
   • Area-Codes.com: Offers a free area code lookup tool with a very detailed database.

With these methods, you can easily find any US phone code you need.

Now you have mastered all the techniques for calling the United States. Remember the most critical point: the US country code is +1.

By following the standard format +1 (area code) local number, you can avoid common mistakes like confusing area codes with country codes. Dialing is a simple standardized process—as long as you follow the rules, you can connect easily.

If you need to make frequent calls, consider using VoIP services or prepaid calling cards, which are usually more cost-effective than direct dialing. We recommend bookmarking this article for quick reference to this important US phone code.

FAQ

Before you make a call, here are quick answers to some common questions to help clear any final doubts.

Is the format the same for US mobile and landline numbers?

Yes, exactly the same. The United States does not distinguish between mobile and landline number formats. All numbers consist of a 3-digit area code and a 7-digit local number, totaling 10 digits. You cannot tell whether a number is mobile or landline just from the number itself.

Do you need to dial +1 when calling within the United States?

No. When calling within the United States, you only need to dial the full 10-digit number (area code + local number). +1 is the country code used for international dialing and can be omitted for domestic calls in the US.

Is calling a US 800 toll-free number from mainland China really free?

No. US toll-free numbers (such as those starting with 800, 888) are only free for callers within the United States.

If you call these numbers from mainland China or other countries, your operator will charge standard international long-distance rates.

What is the format for sending text messages to a US number?

The format for sending text messages to a US number is exactly the same as for making a call. You need to enter the full international number in the recipient field.

The format is:
+1 (area code) local number

For example, to send a text to the New York number (212) 555-1234, you should enter +12125551234.