TL;DR: Free Unified Social Credit Code validator per GB 32100-2015: verifies the 31-char alphabet and weighted mod-31 checksum locally, and parses the registration department and organization category.
This tool runs entirely in your browser. Open DevTools → Network panel and search your input — it appears in no request.
Usage Guide
Invoice headers, business KYC flows, field validation during data integration — the Unified Social Credit Code is a company’s ID number. This tool validates GB 32100-2015 locally: the 18-char, 31-symbol alphabet (no I/O/S/V/Z) plus a weighted mod-31 check over the first 17, and it decodes the registration department (leading 9 = industry-and-commerce enterprise) and organization category.
1. Why no I/O/S/V/Z
The alphabet drops five confusable letters (I/1, O/0, S/5, V/U, Z/2) to cut human and OCR error rates — the same logic behind plates skipping I/O. Checksum: weights [1,3,9,27,19,26,16,17,20,29,25,13,8,24,10,30,28] over 17 chars, 31 minus (sum mod 31), mapped through the alphabet. A leading "91350100" reads as an enterprise registered in Fuzhou, Fujian — 91 is the enterprise fingerprint.
2. Using the parsed output
On success, department/category come from the standard semantics of the first two chars (91 = enterprise, 11 = public institution, 51 = social organization) — handy for live form hints. Format-valid does not mean still-operating: a deregistered company’s code remains checksum-valid; operational status belongs to the market-regulator data APIs.
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