Business ID (Y-tunnus)

Detailed explanation

The Y-tunnus consists of seven digits followed by a hyphen and a check digit (e.g., 1234567-8). This format ensures each identifier is unique and includes built-in error detection. The number is assigned by the Finnish Patent and Registration Office (PRH) or the Tax Administration when a business entity is registered, and it remains with the organization throughout its existence.

Every legally operating business in Finland must have a Y-tunnus. This includes sole proprietors (toiminimi), limited liability companies (osakeyhtiö), partnerships, cooperatives, associations, and even foreign companies with a permanent establishment in Finland. The number appears on virtually all official business documents and is used to track tax obligations, employer responsibilities, and regulatory compliance.

The Y-tunnus is publicly searchable through the Business Information System (YTJ — Yritys- ja yhteisötietojärjestelmä), a free online database maintained jointly by PRH and the Tax Administration. This transparency allows anyone to verify a company's legitimacy, check its registration status, and access basic information about its activities and responsible persons.

How it affects expats

• •Freelancing and self-employment: Starting any business activity requires obtaining a Y-tunnus

• •Verifying employers: You can check potential employers' legitimacy using their Y-tunnus in the YTJ database

• •Invoice requirements: When invoicing businesses, you often need to include your Y-tunnus

• •Tax obligations: The Y-tunnus links your business to tax records and VAT registration

• •Contracts and banking: Business bank accounts and many contracts require your Y-tunnus

• •Starting a company: Essential first step before conducting any commercial activity in Finland

How to get a y-tunnus

• Decide your business form: Sole proprietor is simplest; OY (limited company) offers liability protection

• Register online: Use the YTJ service (ytj.fi) to submit your registration electronically

• Prepare required information: Business name, industry description, estimated turnover, and personal details

• Pay the registration fee: Fees vary by business type (sole proprietors are free; OY costs around 280 EUR online)

• Receive your Y-tunnus: Processing takes 1-5 business days for most business forms

• Register for tax obligations: Separately register for VAT if your annual turnover exceeds 15,000 EUR

Where you will see y-tunnus

• •Business invoices and receipts

• •Company websites (often in the footer)

• •Employment contracts

• •Official correspondence from companies

• •Public procurement documents

• •Trade register extracts

Related terms

• •ALV (VAT) — Value-added tax in Finland

• •YEL (Self-employed pension insurance) — Pension insurance for self-employed people

• •Foreigner's ID number (HETU) — The Finnish personal identity code used by authorities and many services

• •Tax card (Verokortti) — Shows your withholding rate