Validate 8-digit Taiwan Unified Business Numbers (UBN / 統一編號). Supports the April 2023 modulo-5 rule, legacy modulo-10 rule, special 7th-digit logic, and batch processing.
| Digit | D1 | D2 | D3 | D4 | D5 | D6 | D7 | D8 | Total Sum |
|---|---|---|---|---|---|---|---|---|---|
| Digit | |||||||||
| Weight | |||||||||
| Product | |||||||||
| Digit Sum |
Validate 8-digit Taiwan Unified Business Numbers (UBN / 統一編號). Supports the April 2023 modulo-5 rule, legacy modulo-10 rule, special 7th-digit logic, and batch processing. Use it for everyday work, development, learning, or quick verification.
This tool runs in your browser. Before working with sensitive data, make sure you trust your browser and device environment.
The Unified Business Number (UBN), commonly known as Tong-Bian (統一編號) in Taiwan, is an 8-digit unique identifier assigned to companies, sole proprietorships, and government agencies for taxation and official registration. UBN numbers are verified through a weighted checksum algorithm using the weights [1, 2, 1, 2, 1, 2, 4, 1]. Each digit is multiplied by its corresponding weight, and the sum of the digits (tens and ones place) of each product is calculated and totaled.
Prior to April 2023, the legacy standard required the weighted total sum to be divisible by 10 (sum % 10 === 0). Due to rapid growth in registered businesses, the Ministry of Finance updated the standard in April 2023 to require divisibility by 5 (sum % 5 === 0). Because any number divisible by 10 is also divisible by 5, all legacy numbers remain valid while dramatically expanding the number pool.
There is a well-known special rule when the 7th digit is 7: 7 multiplied by weight 4 equals 28, and 2 + 8 = 10. Under official guidelines, this digit sum can be treated as either 1 (1 + 0) or 0. If either resulting total sum is divisible by 5 (or 10 under legacy rules), the ID is declared valid.
This tool processes everything client-side in your browser. Whether you need to verify a single ID for invoicing or batch-validate hundreds of entries, you get instant results without uploading any data to external servers.
The Ministry of Finance changed the divisibility criterion from modulo 10 to modulo 5, doubling the pool of available valid company numbers while maintaining 100% backward compatibility.
When the 7th digit is 7, 7 * 4 = 28, leading to a digit sum of 10. The Ministry allows this sum to be counted as either 1 or 0. If either variant satisfies the divisibility rule, the number is valid.
No. The checksum validator only verifies mathematical syntax and format correctness. To confirm active corporate registration status, check the Ministry of Economic Affairs (MOEA) registry.
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