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Common Mistakes to Avoid When Formatting US Phone Numbers



Common mistakes to avoid when formatting US Phone Numbers

You see 👀, formatting US phone numbers needs to be done right, and despite its simplicity, we usually do it wrong. 

These mistakes can 🤯complicate a reader and cause more misunderstandings🤷‍♂️, especially where communication through a phone number is concerned. 

You must avoid common🤝 mistakes to ensure that your US phone numbers are presented clearly and professionally. Common errors include the wrong area code, using the wrong format, not verifying the phone number, applying unnecessary characters, and many more. 

This blog will explain common mistakes you can avoid while formatting US phone numbers. We also cover best practices you can use when formatting the US phone number. 


  • To properly format US phone numbers, you should avoid common mistakes, including using the wrong standard format, neglecting the country code, not verifying the number, and more.
  • The US phone number consists of 10 digits, of which 3 are the area code, 3 are the central office code, and 4 are the line number.
  • When dialing a US phone number from another country, misplacing the country code (+1) can lead to misdirection and a connection to the wrong destination.
  • To properly format US phones, you can implement practices such as following industry standards, using extensions correctly, leveraging technology, and many more.

Why proper US phone number formatting is essential? 

Proper US phone number formatting is essential because it is easy to read and improves business and data processing outcomes. It divides numbers into parts that can easily be comprehended by the reader or user. This formatting also corrects international dialing and standardizes numbers to the E. 164 formatting.

Moreover, The structure of a standard US phone number consists of 10 digits. The first 3 digits represent the local area code, the next 3 digits represent the central office code, and the last 4 digits represent the line number.

Let’s take a real-life example of the White House in Washington, D.C.,

  • The area code of Washington, D.C. is 202.
  • The Central Office Code is 456
  • The line number is 1111.

Finally,  The format of 10 digits Washington D.C., US phone number is like this: (202) 456-1111 

8 Common mistakes to avoid when formatting US phone numbers

Sometimes, Formatting the US number can lead to errors and inefficiencies. It’s not just about getting it right but also about avoiding common mistakes for a better format. 

Top mistakes to avoid when formatting US Phone Numbers

Here are 8 common mistakes you should avoid when formatting the US phone number.

1. Ignoring US Standard Formats

If the country code is not included when calling a US phone number from another country, the call either does not go through or connects to an incorrect number or device. This is a standard error that occurs while dialing an international phone call, and people often get disoriented because of this mistake. 

For example, when calling the WhiteHouse from another country, use 202 456 1111 instead of +1 202 456 1111

2. Including Unnecessary Characters

Besides the chosen number, adding additional figures like space, hyphens, or parentheses might create confusion each time the number is dialed or typed into a system. This often happens when typing numbers, leading to misunderstanding and frustration, especially when dialing phone numbers. 

For example, you might use (202) 456-1111 to refer to the number instead of 202 456 1111

3. Neglect Country Code

The omission of the initial digit (1) when dialing from another country to the USA may make the call unconnected or cause it to connect to the wrong number. This mistake is typical, especially when dialing the international line, which might annoy you. 

For example, instead of using the international code +1, you may call the White House from another country and dial 202 456 1111

4. Use of Wrong Area Code

When a wrong local area code corresponding to a particular region in the US is dialed, the call may be wrong-connected, or the intended recipient may be confused. This is especially true when dialing local numbers, but it can also lead to a delay or inability to make a call. 

For example, calling New York instead of Washington, D. C., by typing 212 instead of 202.

5. Incorrectly entering phone number digits

When one types the number on the phone, there is a high chance that one could key in the wrong digits, resulting in either failed or wrong connections. This mistake often occurs when entering phone numbers and makes people confused or even angry.

For example, instead of using the correct White House number – 202 456 1234 – they dial 202 456 1111

6. Not Verifying The Number Before Dialing

This might cause call failure or a wrong call connection if a phone number is not appropriately confirmed before dialing it. It is a common error experienced while writing phone numbers where the last digits get intertwined and create great inconvenience.

For example, dialing an invalid or a number in a different region

7. Using The Wrong Format

If a call is made using a different format of dialing the US phone number, it makes the call fail or be completely confusing. This is usually a painful mistake, especially when dialing phone numbers, which leads to confusion. 

For example, instead of using the international format of +1 202 456 1111, one can type 202 456 1111

8. Assuming All US Number Starts with “1”

Supposing every telephone number in the United States begins with the digit “1” can create misunderstandings and missed connections. This is a familiar error made when calling internationally and tends to confuse the parties involved.

For example, instead of using the international format of +1 202 456 1111 while calling the White House from a foreign country, one may use 001 202 456 1111

Best practices for formatting US phone numbers 

Here is the list of practices you can follow while formatting US phone numbers.

  • Follow Industry Standard: The phone number format should be (XXX) XXX-XXXX, where the area code will be enclosed in parenthesis, and a hyphen will be used between the prefix and suffix. Make sure that the number’s area code, prefix, and suffix sections are placed and divided correctly, depending on the chosen pattern. 
  • Leverage Technology: Ensure that formats and conventions used in all systems and applications are standardized to enhance data coherence. Use good number validation and verification techniques to enhance the quality of the data to be entered into the phone number fields. 
  • Use Extensions Correctly: Utilize formatted extensions correctly, such as telephone number format including (XXX) XXX-XXXX, XXX-XXXX, or 1-XXX-XXXX based on the context. Ensure that extra numbers and extensions are listed and spaced clearly for customers to see, along with the core business telephone number. 
  • Include Country Code: Employ the international format incorporating the country code (for instance, +1 for the United States) for phone numbers that will be utilized internationally. This helps reduce confusion and ensure that all calls are properly allocated through the right channels. 
  • Common Formats: It is recommended that you learn the most frequently used numbering plans, such as (NPA) NXX-XXXX, NPA-NXX-XXXX, or 1-NPA-NXX-XXXX. Explain each component’s meaning and proper formatting (NPA, NXX, XXXX). 
  • Train Employees: Teach employees the correct format for displaying US phone numbers so that the format conforms with an organization-wide standard. Offer on-the-job training on the standard formats, data entry protocols, and the general or company-specific requirements or conventions that may apply to the company. 
  • Avoid Punctuation: Do not use punctuation marks other than brackets and hyphens, such as commas, periods, or colons, to avoid causing compatibility and interface problems in different systems and applications. No changes should be made to it because the formatting rules should be followed strictly to preserve the data. 
  • Audit and Cleanse Data: It is also necessary to check the phone number dataset and eliminate mistakes on a regular basis. This helps ensure that the contact information input in the database is correct and up to date.
  • Establish Data Governance: Phone numbers should be well managed and maintained by having proper policies and procedures in data governance. This involves showing how data will be formatted and structured, who is responsible for inputting data, and how the data will be verified and updated.


Formatting US phone numbers can be easy if you consider mistakes such as ignoring US standard format, neglecting country code, and including unnecessary characters. It is necessary to learn the format of the US phone number, which is a 3-digit area code, then a 3-digit exchange code, and finally a 4-digit line number. Thus, by adopting this structure, you can be confident that your phone numbers are properly formatted and possible to read. 

Therefore, it is crucial not to make common mistakes like writing in the wrong position, using the wrong separator, adding the wrong additional characters to the phone number, and so on. By observing the formatting standards outlined above, one can format the phone numbers appropriately and thus communicate the relevant information as intended. 

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Dinesh Silwal

Dinesh Silwal is the Co-Founder and Co-CEO of KrispCall. For the past few years, he has been advancing and innovating in the cloud telephony industry, using AI to enhance and improve telephony solutions, and driving KrispCall to the forefront of the field.

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