Must-read for data cleaning in the United States: How to unify numbers into E.164 format (country code, spaces, brackets and duplicate number processing)

When your U.S. customer acquisition data comes from a variety of sources—form registrations, offline events, third-party lists—number formats tend to come in all kinds of shapes. Some have parentheses and hyphens, such as (415) 123-4567; some have only 10 digits, such as 4151234567; some have the US domestic long distance prefix 1 but no ”+” sign, such as 14151234567. When these irregular data are directly uploaded to the screening platform (such as KK-DATA) for Telegram/WhatsApp/Line screening, it is likely to lead to identification errors, invalid matching and even repeated deductions. Unifying to E.164 format is the first step in bulk US number detection and is the key to avoiding wasting time and balance.

This tutorial will teach you step by step how to clean U.S. data: understand the E.164 standard, use Excel/regular/platform tools for batch conversion, verify format correctness, and deal with duplicate numbers. Whether you are doing cross-border e-commerce to acquire customers overseas, or operating a local community in the United States, this guide can help you improve the quality of U.S. screening data.

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Why does US data need to be unified into E.164 format?

Number screening platforms (including KK-DATA Console) rely on international standard number formats to identify the location, operator and valid digits when processing numbers. E.164 is a global telecommunications numbering plan developed by the International Telecommunications Union (ITU). Almost all communication systems (SMS, voice, instant messaging registration) adopt this specification. If the US data you upload is not in E.164 format, the following problems may occur:

• Misjudgment of country of origin: When the country code +1 is missing, the platform may parse according to the rules of other countries, resulting in completely wrong verification results.
• Invalid number: Strings containing spaces, brackets, and hyphens may be judged as “invalid format” and the number screening task will be skipped directly.
• Duplicate deductions: If the same number appears multiple times in different formats (such as +14151234567 and 14151234567), the platform may deduct the balance as different numbers, but in fact it should be deduplicated.
• Match failed: Some screen number detection relies on accurate number string comparison. Inconsistent formats will reduce the hit rate.

Necessity of cleaning: Even if you have a “clean” list, it is best to do a format conversion and deduplication. This usually only takes a few minutes, but can greatly improve the accuracy of subsequent screen number delivery.

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What is the E.164 format? Standard way to write U.S. numbers

The rules for the E.164 format are very simple:

• starts with +
• followed by country code (1~3 digits)
• Followed by the area code and user number (the total length does not exceed 15 digits)
• Does not contain spaces, brackets, hyphens, or any symbols other than the plus sign

For the United States (including Canada and other North American countries), the country code is 1. The local number in the United States is 10 digits (3-digit area code + 7-digit local number). Therefore, the standard E.164 writing method for U.S. numbers is:

+1 + 10位数字 → 共13个字符

Example: A number in San Francisco is written +14151234567 (instead of 415-123-4567 or +1-415-123-4567).

H3: Common format errors in US numbers

Error type	Example	Description
Missing country code	4151234567	Only 10 digits, the platform cannot identify it as the United States
Keep spaces/brackets/hyphens	(415) 123-4567 or 415 123 4567	Contains non-numeric characters, illegal format
Use domestic long-distance prefix but no + sign	14151234567	The starting number 1 is different from +1 and may be regarded as an 11-digit number starting with 1
Redundant international prefix	01114151234567	The international dialing prefix (011) does not comply with the E.164 standard
Duplicate country code	+1+14151234567	Two + signs, wrong format

H3: Why is +1 necessary?

When the number screening platform analyzes the number, it first determines the place of origin based on the country code at the beginning. If the number does not have +1, the system may try to use the default country (such as China +86) to parse, or directly report an error. Only when the correct country code is added, the platform can determine that the number belongs to the US market and select the corresponding detection channel (such as US local WhatsApp, US Telegram server, etc.). Even if the content of a number missing +1 is correct, it may be discarded as invalid data.

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Preparation work before US data cleaning

Before converting the format, please do three things:

1. Back up original data Keep a copy of the original file without any modification to prevent data loss caused by misoperation.

2. Confirm that the data columns are in order If the data is in Excel or CSV, make sure that “Number” occupies its own column and is not mixed with other fields (such as name, email address). It is recommended to clean up the header rows and redundant blank rows.

3. Preliminary Duplication Removal Using Excel’s “Remove Duplicates” or text tool to remove duplicates can reduce the workload of subsequent conversions. But note: The same number in different formats may not be recognized as duplicates (such as 4151234567 and 14151234567), so it is best to do the deduplication again after unifying the format.

4. Check file encoding It is recommended to save the CSV file as UTF-8 encoding to avoid garbled special characters. When saving as CSV in Excel, you can select “CSV UTF-8 (comma separated)”.

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Step-by-step operation: Unify US numbers into E.164 format

Three common methods are provided below, which you can choose based on the amount of data and technical level.

H3: Method 1: Use Excel formulas for quick conversion

Suppose the number is in column A, and column A may contain various formats (such as (415) 123-4567, 4151234567, 14151234567). We need to complete it in two steps:

Step 1: Remove all non-numeric characters (retain numbers 0-9) Enter the following formula in B1 (for Excel 2016 and above):

=SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(A1," ",""),"(",""),")","-"),"-",""),"+","")

This formula will remove spaces, left brackets, right brackets, hyphens, and plus signs in order. If you just want to keep numbers, you can also use a more general approach:

=TEXTJOIN("",TRUE,IFERROR(MID(A1,ROW(INDIRECT("1:"&LEN(A1))),1)*1,""))

For most U.S. numbers, however, the former formula is more intuitive.

Step 2: Check the length and add +1 Enter in C1:

=IF(B1="","",IF(LEN(B1)=10,"+1"&B1,B1))

This logic: If the length after cleaning is 10 (only local US numbers), add +1 at the front; if it is already 11 digits (the starting 1 may be a domestic prefix), leave it as it is (but you actually need to confirm whether the beginning is 1). A more rigorous approach is: first unify them into pure numbers, then uniformly intercept the last 10 digits and add +1.
It is recommended to use the final formula (assuming that non-numbers have been removed from column B):

=IF(LEN(B1)=10,"+1"&B1,IF(LEFT(B1,1)="1" AND LEN(B1)=11,"+1"&RIGHT(B1,10),B1))

This can handle 10-bit and 11-bit situations at the same time.

Step 3: Drop down to fill, then copy column C and paste as value to get the standard E.164 number.

H3: Method 2: Use a text editor (such as VS Code/Notepad++) to perform batch regular replacement

It is suitable for processing large numbers (thousands to hundreds of thousands of lines) and operates more quickly.

1. Open a text file (one number per line, e.g. plain text columns exported from CSV).
2. First Replacement: Find [^0-9] and replace it with empty. This will remove all non-numeric characters, leaving a purely numeric string.
   • Check “Regular Expressions” in Notepad++.
   • Note: If the number contains letters, they will also be deleted, but US numbers should only have digits.
3. Second Replacement: Add +1 at the beginning of each line, but be careful: some numbers may already start with +1. It can be processed into pure numbers first and then added together.
   • Replace find ^ with +1.
4. But there is a case of 11 digits: If the pure number length is 11 and starts with 1, there is no need to add +1, and deduplication logic is required. A safer approach is:
   • After the first replacement, use search to replace ^1(\d{10}) with +11 (convert the 11 digits starting with 1 to +1 + the last 10 digits).
   • Find ^(\d{10}) and replace it with +11 (add +1 directly to the 10-digit number).
   • Numbers of other lengths are marked as invalid.

This two-step regularization method can achieve error-free conversion.

H3: Method 3: Use the KK-DATA global number generation and cleaning function

If you are using the KK-DATA Console, you can get numbers in a standard format with the help of its built-in Global Number Generation module. For example, if you need random number segment data from the United States, you can generate it directly according to conditions. The generated results come with E.164 format.
For an existing number list, the system will perform basic format verification and give format suggestions before submitting the number screening task. Although the platform itself does not provide automatic cleaning (users are required to upload a standard format), you can refer to the instructions on number format in Documentation to ensure data compliance.

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How to check whether the cleaned number complies with E.164?

After cleaning is completed, it is recommended to verify according to the following steps:

• Length Check: A valid US E.164 number should be 13 characters (+1 + 10 digits). Use the Excel formula =LEN(A1) to check and if it is not 13, mark it.
• Regular verification: Use regular ^\+1[0-9]{10}$ matching in the text editor. Unmatched lines are exceptions.
• Sampling Test: Randomly select 50~100 cleaned numbers, dial them manually or check their format through other verified tools.
• Small batch test run screening number: Submit a small task of 100~500 items in KK-DATA Console and observe whether the detection results are normal (for example, it is recognized as a US number, and there is an activated/active return). If everything is OK, then process all data.

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Deduplication of numbers after unified format

Even if you have done preliminary deduplication before cleaning, the same numbers in different formats may become the same string after conversion. Therefore, final deduplication should be done after the format is unified:

• Select the organized E.164 number column in Excel and use “Data → Delete Duplicates”.
• In a text editor, duplicate lines can be removed manually after sorting, or using the uniq command (Linux/Mac) or a plugin.
• When submitting a task in KK-DATA Console, the platform comes with the Data Deduplication Warehouse function, which can automatically remove duplicates across tasks to avoid wasting balances due to repeated detection. This is a worry-free way to manage your US customer acquisition data long-term.

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FAQ

**Q: What is the difference between the country code “+1” and “1” for US numbers? Why must we add ”+”? ** Answer: The E.164 standard stipulates that international numbers must start with ”+”, indicating international dialing. In mobile communications and Internet applications, ”+” is a mandatory prefix. The lack of ”+” may cause the system to mistake it for a domestic number and fail to parse it correctly. Therefore, the screen number platform requires the use of “+1” instead of simply “1”.

**Q: There are some Canadian numbers (also starting with +1) in my US data, how to deal with them? ** Answer: The United States and Canada share country code 1, so the format is exactly the same (both +1+10 digits). When filtering the number, the platform will further identify the area code to determine the country. You don’t need to differentiate, just keep +1. If you only need the United States, you can subsequently filter by the area code range (for example, 201, 202, etc. belong to the east coast of the United States, but the filter code results may also include Canada; it depends on the platform capabilities).

**Q: I have used a formula to change the number to +14151234567, but when I upload it to the customer system, it prompts a format error. What should I do? ** Answer: Please confirm whether the target system strictly follows the E.164 standard. Some platforms allow spaces or hyphens, but for the sake of universality, it is recommended to only use the purely numeric form +14151234567. You can use a text editor to double-check whether there are extra spaces or invisible characters (such as tabs). You can paste the data into Notepad first, and then copy it back to Excel from Notepad to clear the hidden formatting.

**Q: After cleaning, some numbers are 12 digits in length (+1 plus 9 digits), and some are 14 digits in length. What should I do? ** Answer: Abnormal length indicates that there may be errors in the original data (such as missing or extra digits). It is recommended to mark these abnormal lines individually and manually verify the original source. For a real US number, the 10-digit local number plus +1 must be 13 digits. Any deviation should be regarded as invalid data and should not be directly completed.

**Q: Can KK-DATA’s “Global Number Generation” help me convert my existing numbers to format with one click? ** Answer: Currently, the platform does not have the function of directly “cleaning uploaded data”, but you can use the global number segment generation we provide to create a standard number, or you can clean it yourself by referring to the method in this article. The platform documentation clearly requires that the uploaded number must be in E.164 format. If you encounter a format error when submitting a task, you can check and adjust according to this article.

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**Ready to improve the quality of your US data? ** Immediately upload the cleaned E.164 numbers to KK-DATA Console for batch screening and detection of Telegram/WhatsApp activation, activity and gender. If you have any questions about the format, please Two-way contact customer service https://t.me/kkdata_robot for real-time help. For more documentation, please refer to KK-DATA Usage Guide.