How this checker works
You paste a LEI. The tool checks three things, in your browser: that the code has exactly 20 characters, that it uses only the letters A to Z and the digits 0 to 9, and that the last two characters, the check digits, agree with the rest of the code under the ISO 7064 MOD 97-10 rule. It then takes the code apart so you can see the issuer prefix, the entity part and the check digits, and gives you a link to the GLEIF record.
It does not query GLEIF, so nothing you type leaves the page. That also means it cannot tell you whether the LEI is registered, lapsed or retired: a well-formed code and an active registration are two different questions. The GLEIF link answers the second.
What a LEI is made of
The Legal Entity Identifier is defined by ISO 17442. It is a 20-character alphanumeric code with a fixed structure:
- Characters 1 to 4: a prefix identifying the Local Operating Unit (LOU) that issued the code.
- Characters 5 and 6: reserved, set to 00.
- Characters 7 to 18: twelve characters assigned by the issuer to the entity, with no embedded meaning.
- Characters 19 and 20: two check digits.
Every LEI is unique and refers to exactly one legal entity. The code itself carries no information about the entity beyond the issuer prefix; the identity data sits in the GLEIF record.
The check digits
The two check digits are computed with ISO/IEC 7064 MOD 97-10, the same scheme an IBAN uses. Each letter is replaced by a number (A is 10, B is 11, up to Z is 35), the resulting number is divided by 97, and the check digits are chosen so that the remainder is 1. The checker runs that division: a remainder of 1 means the code is internally consistent; anything else means at least one character is wrong, typically a transcription error. The standard also rules out 00, 01 and 99 as check digits.
The LEI and the DORA register of information
The register of information under DORA identifies the financial entity and its ICT third-party providers by LEI where one exists, and the CSSF has made the LEI a practical prerequisite for the Luxembourg submission: the entity's LEI has to be communicated to the CSSF before the register can be filed through eDesk. A malformed LEI in the register is a validation error, and the 2026 CSSF collection showed that most refused registers fail on a handful of identifier and cross-reference errors rather than on substance.
Checking each LEI before it goes into the register is cheap; finding it during the ESA validation window is not. This checker is for the one-off check. For a register of dozens of providers, the validation belongs in the record itself.
Frequently asked questions
Does a valid format mean the LEI is active?
No. The check confirms the code is well-formed. Whether it is registered, who it belongs to and whether it has lapsed are in the GLEIF record, which the link opens. A LEI has to be renewed every year.
Why does the DORA register of information need LEIs?
The register identifies the financial entity and its ICT third-party providers by LEI where one exists, so supervisors and the ESAs can link arrangements across the EU. The CSSF also requires the reporting entity's LEI to be communicated before the submission.
Where do I get or renew a LEI?
From an accredited issuer, a Local Operating Unit, or a registration agent; GLEIF lists them. Renewal is annual.
Can I check several LEIs at once?
This checker takes one code at a time. Klavius validates the LEI format for every provider in the ICT third-party register on import and flags the ones to correct.
Where does the LEI I enter go?
Nowhere. The check runs in your browser and the page makes no call to GLEIF or to anyone else; the link to the record is a link you open yourself.
Sources
- ISO, ISO 17442-1:2020, Financial services, Legal entity identifier (LEI), Part 1: Assignment, 2020.
- GLEIF, ISO 17442: the LEI code structure.
- ISO/TC 68, What is LEI?.
- CSSF, DORA: submission timeframe for register of information, eDesk portal open as of 11 February 2026, 11 February 2026.
- CSSF, DORA: Register of Information collection, update, 17 March 2026.
Where Klavius fits
In Klavius the LEI lives on the provider record. The ICT third-party register validates the format of every LEI on import, flags the ones to correct, and carries them into the register of information, so a code is checked once, where it lives, rather than found by the validator after the deadline. See how Klavius handles DORA, and what the 2026 collection taught Luxembourg fund managers.