USCC · GB 32100-2015

USCC validator

Paste the 18-character code from the supplier business licence; the validator runs the GB 32100-2015 Mod 31 check digit and tells you whether the code was probably typed correctly. A pass does not confirm the company is real or active. Cross-check on Tianyancha or Qichacha before wiring funds.

Last updated 2026-05-08. Math runs in your browser, no data leaves your computer.

General guidance only, not legal or professional engineering advice. Verify against the cited primary sources (IMDG, REACH, ChAFTA, RCEP, Customs Tariff Act, supplier SDS, etc.) before committing to a shipment, declaration, or contract. Sourzi assumes no liability for outcomes based on these calculators.

Take the 18-character code from the supplier business licence (top-right of the licence card). The validator runs the alphabet check, the structural check, and the Mod 31 check digit per GB 32100-2015. Math runs in your browser, the code is not sent anywhere.

Eighteen characters. Letters are uppercase; the alphabet excludes I, O, S, V, Z to avoid ambiguity in print and handwriting.

The Mod 31 algorithm

GB 32100-2015 specifies a 31-character alphabet (the digits 0 to 9 plus the uppercase letters A to Y, excluding I, O, S, V, Z) and a Mod 31 check-digit calculation. Each character maps to a numeric value: 0 to 9 keep their digit value; A through Y map to 10, 11, 12 and so on, skipping the excluded letters. The validator multiplies each of positions 1 to 17 by a fixed weight (1, 3, 9, 27, 19, 26, 16, 17, 20, 29, 25, 13, 8, 24, 10, 30, 28), sums the products, takes the result modulo 31, and computes the expected check digit as (31 minus sum mod 31) mod 31. If the resulting numeric value matches the value of position 18, the code passes.

The Mod 31 design is deliberate. Mod 11 (used in older Chinese ID and tax codes) catches single-digit typos and adjacent transpositions but misses double transpositions. Mod 31 with mixed prime weights catches most typo patterns including the common adjacent-character swap. The design trade-off: a wider alphabet is harder to read aloud over the phone, easier to scan from a printed document. SAMR chose printed-document robustness because the USCC is the customs declaration master key.

A check-digit pass is a typing-correctness signal. It does not confirm the entity is real, active, or trading. A code can be structurally valid but belong to a deregistered shell, a suspended manufacturer, or an entity that never traded. The first thing to do after a pass is open Tianyancha or Qichacha and confirm the entity is in 在营 (active) status, the registered capital matches the supplier claim, the legal representative is the person you have been talking to, and the business scope (经营范围) covers the goods you are buying.

For chemical procurement specifically, the business scope wording matters. A company whose scope is 化学品销售 (chemical sales) but not 化工产品生产 (chemical manufacturing) is a trader, not a factory. Many supplier disputes start here. The USCC is the entry point; the rest is on the registry.

Worked example. USCC 91110000600005638L

The booking. A US buyer receives the Proforma Invoice from a Chinese supplier with USCC 91110000600005638L printed at the top. Buyer wants to wire 30 percent deposit (16,200 USD on a 54,000 USD order) and ships in 14 days. The buyer pastes the USCC into the validator. Position 1 is 9 (SAMR-registered), position 2 is 1 (limited liability company), positions 3 to 8 are 110000 (Beijing municipality), positions 9 to 17 are 600005638 (the entity sequence), position 18 is L. The Mod 31 sum of the 17 weighted values lands at 662 mod 31 = 11; expected check is (31 minus 11) mod 31 = 20 in numeric value, which maps to L in the GB 32100-2015 alphabet. Code passes the structural check. Looks fine on paper.

The failure. Buyer wires the deposit. Two weeks later the supplier asks for the balance and says shipment is ready. Buyer wires the balance. Three weeks later cargo has not arrived. Bank confirms the receiving account is held by a different company, not the one named on the PI. Buyer pulls up Tianyancha and finds the USCC he validated belongs to a Beijing trading company that was deregistered (注销) eighteen months ago. The validator never said the company was active; only that the typing was correct. Buyer learns the difference the expensive way.

The fix. On the next supplier, the buyer runs the validator first, then opens Tianyancha and confirms the entity is in 在营 status, the legal representative on Tianyancha is the same name on the PI, the registered capital is meaningful for the order size, and the business scope covers chemical manufacturing not just trading. Five-minute check, saves the next 54,000 USD. The validator is the typing check; the registry is the existence check; the bank wire instructions are the routing check; the order ships only after all three pass.

Frequently asked

What is a Unified Social Credit Code?

The Unified Social Credit Code (统一社会信用代码 USCC) is the 18-character identifier issued by the State Administration for Market Regulation (SAMR) to every Chinese legal entity, social organisation, and government body. Introduced in 2015 under GB 32100-2015, it replaced the older 9-digit Organization Code Certificate plus the 15-digit business registration number with a single number that travels across tax, customs, and banking.

How is the USCC structured?

Eighteen positions, broken into five blocks. Position 1 is the registration management department (e.g. 9 for SAMR-registered companies, 5 for civil affairs). Position 2 is the entity category. Positions 3 to 8 are the GB/T 2260 administrative jurisdiction (the 6-digit area code). Positions 9 to 17 are the entity sequence assigned by the registry. Position 18 is the check digit, computed against positions 1 to 17 using a Mod 31 algorithm specified in GB 32100-2015.

Why does the validator say a USCC is structurally valid but I still can not find the company?

A check-digit pass tells you the 18 characters were probably typed correctly. It does not tell you the company is real, active, or trading. Verify on Tianyancha or Qichacha for current status, paid-in capital, and litigation history. The validator catches typos; it does not catch fraud.

Can the validator confirm whether the company is active?

No. A USCC stays valid as a number even after a company is deregistered, revoked, or suspended. To check current status (在营 / 注销 / 吊销), use the SAMR public lookup at gsxt.gov.cn or the commercial trackers like Tianyancha and Qichacha.

Why does the algorithm exclude I, O, S, V, Z from the alphabet?

I and O are excluded because they look like 1 and 0 in print. S, V, and Z are excluded because they are easy to confuse with 5, U, and 2 in handwritten Chinese-form documents. The 31-character alphabet (0 to 9 plus A to Y minus I, O, S, V, Z) is the GB 32100-2015 specification.

My supplier sent me a code that is 15 digits, not 18. Is that a USCC?

No. A 15-digit number is the older business registration number (营业执照注册号) used before 2015. Most companies were re-issued an 18-character USCC in the 2015 to 2018 unification. If your supplier still uses a 15-digit number on documents, ask for the current USCC and check it on the SAMR registry. Customs declarations require the 18-character USCC.

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