Unified Social Credit Code checker: structure and check digit.

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18-character Unified Social Credit Code Check structure and check digit

This runs entirely in your browser. The code you type is not transmitted, stored or logged.

How the 18 characters are built

GB 32100-2015 fixes both the length and the layout. Every mainland legal entity and organisation carries one code, printed on the business licence.

Positions defined by GB 32100-2015

Positions	Part	Length
1	Registration authority code	1
2	Entity category code	1
3–8	Administrative division code	6
9–17	Subject identifier (organization code)	9
18	Check character	1

What the first two characters tell you

Position 1 is the registration authority and position 2 is the entity category under it. The pairing most buyers care about sits under market regulation (code 9):

Entity categories under registration authority 9 (工商 / market regulation)

Starts with	Entity type	Chinese
91	Enterprise	企业
92	Individually-owned business	个体工商户
93	Farmers specialised cooperative	农民专业合作社

An individually-owned business is run by a natural person, so its liability and scale differ from a company’s — and a licence photo will not tell you which one you are dealing with. The second character will.

It does not settle whether they can export. Individually-owned businesses trade internationally too. The 2004 revision of the Foreign Trade Law brought individuals within the definition of a foreign trade operator, and on 30 December 2022 the Standing Committee of the National People’s Congress removed the foreign-trade-operator filing requirement altogether, with filing stopped from that date. Export eligibility turns on the registered scope and customs registration, not on the entity type.

Other authorities appear in the first position too — 1 for centrally staffed bodies, 5 for civil-affairs registrations such as foundations and social organisations, N for rural collective economic organisations, and several more.

Where it is registered

Positions 3–8 hold the GB/T 2260 administrative division code. The checker reads only its first two digits, which give the province — 11 Beijing, 31 Shanghai, 44 Guangdong, and so on. City and county codes are deliberately not decoded: they change with boundary and naming reforms, and a stale place name is worse than none, because buyers compare it against the contract address.

Codes beginning 71, 81 or 82 map to Taiwan, Hong Kong and Macau. Those are not registered by SAMR, so a mainland business licence would not carry them.

Character set

Codes use digits and uppercase letters, but the standard excludes I, O, Z, S and V because they are read too easily as 1, 0, 2, 5 and U. Seeing any of those five in a code you were sent almost always means it was mistyped rather than forged.

Check digit

The eighteenth character is calculated from the first seventeen. Each position has a weight of 3⁽ⁱ⁻¹⁾ mod 31, and the check character satisfies C18 = 31 − (Σ Ci × Wi mod 31), taken modulo 31 so that a result of 31 becomes 0. A single mistyped character will therefore almost always fail.

What a passing code proves — and what it does not

This is the part most tools leave out, and it is where buyers lose money.

It proves

• The 18 characters are internally consistent, so the code was transcribed correctly.
• The code is formatted as GB 32100-2015 requires.

It does not prove

• That the company exists. A correctly formed code can be constructed by anyone who knows the algorithm — including the one on this page.
• That the company is still active rather than revoked or deregistered.
• That its registered business scope covers what you are buying.
• That it may legally export to you. Export eligibility turns on the company’s registered scope and its customs registration. Neither is encoded in this number, and the entity type does not settle it either — individually-owned businesses can trade internationally too.
• That this company is the one issuing your invoice or receiving your payment. Those are frequently different entities, which is routine — but it needs saying out loud before money moves.

Answering any of those requires the live registration record, not the code itself. The registry check guide sets out the official route, including what to do when the portal will not open from where you are.

Sources

• GB 32100-2015 Rules for the code of legal entities and other organizations — structure, character set and check-digit rule. National standard, in force since 1 October 2015.
• National Enterprise Credit Information Publicity System (GSXT) — the official registration record itself.

This page implements the encoding rule only. It does not query any registry, and it is not legal advice or a conformity assessment.