Validate the format and checksum of a 10-digit Korean business registration number. This does not confirm actual registration.
※ This only verifies the checksum format. To confirm the business is actually registered with the National Tax Service, use Hometax's business status lookup.
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Every Korean business gets a 10-digit registration number in the format XXX-XX-XXXXX. The digits aren't random — the last digit is calculated from the first nine using a fixed weighted checksum, so a single mistyped digit is very likely to be caught.
This checksum only guards against typos — it doesn't confirm the business is currently registered, active, or legitimate. Before signing a contract or making a payment, verify the business through Hometax's official lookup or ask for a copy of their business registration certificate.