What is a unified social credit code?

The unified social credit code (统一社会信用代码) is China's 18-character identifier for every registered legal entity, replacing older separate business, organization and tax numbers. It is mandatory on business licences and B2B documents since 2015.

How is the USCC check character calculated?

Each of the first 17 characters maps to a value 0-30 using a 31-symbol alphabet that excludes I, O, Z, S and V. Those values are multiplied by a fixed weight array, summed, and the check character is 31 minus the sum modulo 31, mapped back through the alphabet.

Why are some letters not allowed?

The letters I, O, Z, S and V are excluded because they are easily confused with the digits 1, 0, 2, 5 and the letter U. Removing them reduces transcription errors when codes are typed or scanned.

What do the segments mean?

Position 1 is the registration management department, position 2 the entity category, positions 3-8 the administrative-division code of the registering authority, positions 9-17 the original 9-digit organization code, and position 18 the check character.

Does a valid code mean the company exists?

No. A valid check character only proves the code is internally consistent. To confirm a company is registered and active, check the National Enterprise Credit Information Publicity System. This tool performs no online lookup.

China Unified Social Credit Code Validator

The Unified Social Credit Code (USCC, 统一社会信用代码) is the single 18-character identifier assigned to every legal entity in China under standard GB 32100-2015. It appears on business licences and is required across Chinese B2B contracts, invoicing and KYC. This validator checks the structure and the official check character entirely in your browser.

How it works

The code is split into meaningful segments:

Position 1 — registration management department.
Position 2 — entity category.
Positions 3–8 — administrative-division code of the registering authority.
Positions 9–17 — the original 9-character organization code.
Position 18 — the check character.

The check character uses an ISO 7064 MOD 31,3 scheme. Each of the first 17 characters is mapped to a value 0–30 through a 31-symbol alphabet (0-9 plus uppercase letters, excluding I O Z S V). Those values are multiplied by the fixed weight array 1,3,9,27,19,26,16,17,20,29,25,13,8,24,10,30,28, summed, and the result reduced modulo 31. The check value is 31 - (sum mod 31) (with 31 mapped to 0), then converted back through the alphabet.

Notes

A passing check character confirms only internal consistency, not registration status. The excluded letters I O Z S V keep the alphanumeric code unambiguous when handwritten or scanned. Use the National Enterprise Credit Information Publicity System for live registration status.