🏢Korean Business Number Validator
Validate the checksum of Korea's 10-digit business registration number. Useful for verifying counterparty info, checking before issuing tax invoices, B2B system data integrity, and first-pass risk checks.
How to use
- 1Enter the 10-digit business number.
- 2Checksum validity displays instantly.
FAQ
Does it verify the business exists?+
No. This tool only checks checksum format. Confirm actual registration on Hometax's 'Business Registration Status Inquiry'.
What's a checksum?+
The last digit of the 10 is computed from the first 9 using a fixed rule. Random inputs almost never pass.
Business number structure?+
XXX-XX-XXXXX. First 3 = issuing tax office; next 2 = entity type (individual/corporate); last 5 = serial + checksum.
Different from corporate registration number?+
Yes — corporate registration is 13 digits, for corporations only. Business numbers belong to all businesses (individual or corporate).
Safe to validate my own number?+
All processing happens in the browser — nothing leaves.
Bulk validation in Excel?+
Currently one at a time. For bulk, use Excel formulas or a dedicated script.