Ariregister — registrikood and isikukood

The Ariregister (Estonian Business Register) is operated by RIK (Registrite ja Infosüsteemide Keskus — Centre of Registers and Information Systems) under the Ministry of Justice. It assigns to every Estonian legal entity a registrikood (8 digits), and to every natural person (citizen or e-resident) an isikukood (11 digits). These national identifiers form the root identification for every e-arve invoice, every eMTA declaration and every X-Road interaction.

History — from Aktsiaselts 1995 to the digital register 2002

The Ariregister was created in 1995 with the first Estonian commercial code (Äriseadustik). Back then filings were on paper at regional courts. Full digitisation came in 2002: every filing became mandatorily online. The English e-Business Register portal opened in 2007, making the register browsable from abroad.

In 2014, the e-Residency programme is a game-changer: foreigners get an isikukood and can incorporate an OÜ (Osaühing — private limited company) entirely online in under 15 minutes. X-Road integration (2017) lets eMTA, RIA and RIK consume Ariregister data in real time.

1995       | First Estonian commercial code (Äriseadustik) — Business
           | Register created with an 8-digit registration number
           | (registrikood) per legal entity.
           |
2002       | Full Ariregister digitisation — online filings become
           | mandatory for annual accounts and statutory changes.
           |
2007       | Launch of e-Business Register (English-language portal)
           | making the register browsable from abroad.
           |
2014       | e-Residency programme launched — isikukood now assigned to
           | foreigners, who can incorporate OÜ (private limited
           | companies) entirely online.
           |
2017       | Full X-Road integration — eMTA, RIA, RIK consume Ariregister
           | data in real time.
           |
2019       | PEPPOL ICD 0191 adopted for the Estonian registrikood.
           |
2024-2026  | ~100,000 e-residents registered, ~28,000 OÜ formed via
           | the e-Residency programme since 2014. Public REST API
           | (avare.rik.ee).

Governance — RIK + Ministry of Justice

RIK is a public agency under the Justiitsministeerium (Ministry of Justice). It operates 35+ national registers: Ariregister (companies), Kinnistusraamat (land register), e-Toimik (court files), e-Notar (notary acts), Karistusregister (criminal record). RIK provides the Ariregister public REST APIs (avare.rik.ee) and free unlimited lookups.

Schema — registrikood, isikukood, KMKR

# Estonian national identifiers

## registrikood (legal entity)
  Format     : 8 digits (e.g. 12345678)
  Operator   : RIK / Ariregister
  XML field  : <RegNumber> in e-arve, <CompanyID schemeID="0191"> in PEPPOL
  Lookup     : https://avare.rik.ee/avalik

## isikukood (natural person)
  Format     : 11 digits (G YY MM DD XXX C)
                G   = gender + century (3-4 = 1900s, 5-6 = 2000s)
                YY  = year
                MM  = month
                DD  = day
                XXX = sequence number
                C   = checksum
  Operator   : SMIT (Siseministeeriumi Infotehnoloogia)
  e-residents: prefix 8 / 9 (not a citizen, does not grant nationality)
  XML field  : <PersonalCode> in e-arve

## KMKR (VAT number)
  Format     : EE + 9 digits (e.g. EE100123456)
  Operator   : EMTA
  Link       : registrikood + taxable status -> KMKR generated automatically
  Lookup     : https://ec.europa.eu/taxation_customs/vies/

## PEPPOL identifiers
  ICD 0191   : registrikood (legal entity)
  ICD 9908   : KMKR (VAT number)

Comparison — Estonia vs Finland vs France

Adoption — 100% of legal entities

• ~250,000 legal entities registered in the Ariregister (companies + associations + foundations).
• ~140,000 active companies (turnover > 0), of which ~28,000 OÜ formed via e-Residency since 2014.
• ~1.3M active isikukood — ~1.2M Estonian citizens + ~100,000 e-residents (e-Residency programme).
• 100% of e-arve invoices carry a seller and buyer registrikood — it is the root identifier.
• API REST avare.rik.ee — ~50M requests / year (RIK 2024), free for lookups, paid for bulk packages.

Common pitfalls

• Confusing registrikood and KMKR. registrikood = 8 digits (RIK). KMKR = EE + 9 digits (EMTA). A non-VAT-registered company has a registrikood but no KMKR.
• Confusing isikukood and registrikood. isikukood = 11 digits (person). A FIE (sole trader) operates under their own isikukood — no separate registrikood.
• Forgetting ICD 0191. In PEPPOL, the registrikood must be prefixed by iso6523-actorid-upis::0191:. Without the prefix, the SMP rejects routing.
• e-Resident ≠ tax resident. An e-resident can hold an isikukood and an OÜ but remains a tax resident of their home country. The OÜ itself is an Estonian tax resident.
• Bad checksum. The isikukood checksum algorithm is public (modulo 11). A copy-paste typo triggers ID-kaart validator rejection.

Cross-links

• Estonia hub — full view
• e-arve B2G mandate 2017
• e-Residency programme
• eMTA — tax portal
• X-Road / X-tee
• RIK — e-Business Register
• Avare.rik.ee — public register
• Riigi Teataja — Äriseadustik