# LEI Search > Check the format of a 20-character LEI, including its ISO 17442 check digits. Canonical: https://corpoapi.com/checks/lei-search Type a Legal Entity Identifier and the check reports whether it is twenty characters with valid check digits. This is a check of the number, not a register lookup. GLEIF runs the LEI system and is where the entity behind an LEI is confirmed. ## What the check reads - **Twenty characters** The count runs after spaces are stripped. Nineteen or twenty one characters fail, because an LEI is exactly twenty. - **Letters and digits** An LEI uses digits and the letters A to Z. Lowercase input is folded to uppercase first, so a lowercase paste still checks. - **The check digits** Positions nineteen and twenty are the check digits. The check expands each letter to two digits and takes the whole string modulo 97; a well-formed LEI leaves a remainder of one. - **The reserved characters** Positions five and six are always 00, which is what tells an LEI apart from a similar twenty-character string. The check reads them. - **What this does not check** Whether the LEI was issued, which entity holds it, and whether it is still active. GLEIF holds all of that in its register. ## Where the data comes from - [GLEIF](https://www.gleif.org/): The Global Legal Entity Identifier Foundation runs the LEI system and holds the golden copy of every issued LEI. ## Worked examples ### A well-formed LEI Input: `529900G3SW56SHYNPR95` - **LEI**: 529900G3SW56SHYNPR95 - **Length**: 20 - **Check digits**: ISO 17442 match - **Verdict**: Well formed - **Where to confirm**: GLEIF This is the format example GLEIF uses. The check reads the shape and the check digits, not the entity. ### Two characters transposed Input: `529900G3SW56SHYNPR59` - **Length**: 20 - **Check digits**: Do not match - **Verdict**: Not well formed - **Likely cause**: Two characters transposed Swapping the last two characters breaks the modulo 97 sum, so the number cannot be a real LEI. ### One character short Input: `529900G3SW56SHYNPR9` - **Length**: 19 - **Needed**: 20 - **Verdict**: Not a complete LEI A truncated paste is the commonest mistake, and the length check catches it before the check digits. ## Twenty characters and two check digits An LEI is twenty characters: a four-character issuer code, two reserved zeros, the entity's own code and two check digits. The check digits come from the ISO 17442 rule, which expands each letter to two digits and takes the whole string modulo 97. A valid LEI leaves a remainder of one. - Exactly twenty characters, letters and digits - The two check digits recomputed - The reserved characters in position five and six ## Well formed is not issued The check runs in the browser. Twenty characters with valid check digits prove the string is a well-formed LEI. They do not prove the LEI was issued, that the entity exists, or that the LEI is still active. GLEIF holds the golden copy that answers those questions. - A well-formed LEI does not prove an entity exists - Issued, lapsed and retired are register states - The check never reaches GLEIF ## GLEIF holds the register GLEIF publishes every LEI in its search, with the legal entity behind it and its registration status. Paste the LEI there to confirm it. The LEI is a global identifier, so the entity can be registered anywhere. - Search the LEI on GLEIF - See the legal entity and its status - One identifier across jurisdictions ## FAQ ### Does this tell me which company the LEI belongs to? No. The check reads the number. GLEIF publishes every LEI with the legal entity behind it, its address and its registration status, and its search is the place to confirm a number. ### Does a valid LEI prove the entity exists? No. A valid format means the twenty characters and their check digits are consistent. It does not prove the LEI was issued, that the entity exists, or that the LEI is still active. Only GLEIF can say. ### What do the first four characters mean? They identify the local operating unit that issued the LEI, not the entity and not the country. The entity itself is encoded in the middle characters. ### Why do the check digits matter? They catch a mistyped or transposed character. Without them a number with one wrong character would look exactly as plausible as a real one. ### What is an LEI for? It is a twenty-character global identifier for a legal entity, used in finance and regulation so that one entity has one identifier across markets. It is not a company register number. ### Is the check free? Yes. It is free of charge, with no account. The character layout and the modulo 97 check digits are verified in your browser, so a wrong character costs nothing, and a well-formed LEI uses one of the tool's 5 daily checks.