Korean Business Number Check
Check whether a ten-digit Korean business registration number matches its input format and mathematical check digit. The calculation follows the publicly available eGovFramework business-number routine. It is separate from official registration, identity, and business-status queries.
Key features
- Accept ten digits or the 000-00-00000 display format.
- Calculate the check digit from the first nine digits.
- Show the formatted number and both supplied and calculated check digits.
How to use
- Enter one number using ten digits or the 3-2-5 hyphen format.
- Run the check and compare the supplied and calculated digits.
- Use official NTS services if you need registration or operating-status verification.
Use cases
- Catch some transcription mistakes in a recorded number.
- Test business-number input validation in a form.
- Learn the mathematical role of the last digit.
Frequently asked questions
Does a matching check digit prove a real business?
No. Invented combinations, including all zeroes, can satisfy the mathematical checksum. The tool does not establish business existence or the identity of a counterparty.
What calculation is used?
Multiply the first nine digits by 1, 3, 7, 1, 3, 7, 1, 3, 5 and add them. Also add the tens digit of the ninth digit times five. Compare (10 - sum modulo 10) modulo 10 with the final digit.
Can it show a company name or closure status?
No NTS API is called. Official registration validity and operating-status services query separate government data.
Does it support corporate or personal identification numbers?
No. This tool is for ten-digit business registration numbers, not thirteen-digit identifiers. The example is an arithmetic illustration and does not identify a particular company.
Privacy
Input and results are processed locally in your browser without upload or storage by this tool. XML and string inputs are not executed; results are shown as text. Shared site advertising and analytics may operate separately, but tool-use events do not include your input contents.
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