Filing an income tax return in Finland works differently for companies and for individuals. Companies file their own return based on their financial statements, while individuals mostly review and correct a pre-completed return the Tax Administration prepares for them. This guide covers both, current for 2026.
Corporate Income Tax Returns
A limited liability company (Oy or Oyj) must file its corporate tax return within four months of the end of its financial year, using Form 6B. This deadline has not changed. For example, a company with a financial year ending 31 December 2025 must file by 30 April 2026.
What Needs to Be Included?
- Financial statement information, including a breakdown of specific income and expenses
- A transfer pricing documentation report, where applicable
- A breakdown of any shareholder loans
- Minutes of the Annual General Meeting, if dividends were decided
Deductible and Non-Deductible Items
Some company expenses are only partly deductible, and some are not deductible at all. Representation expenses remain 50% deductible, and donations to certain approved recipients are deductible within set limits. Direct taxes, fines, and compulsory reserves are not deductible.
Individual Income Tax Returns
Most individuals in Finland receive a pre-completed tax return from the Tax Administration each spring, based on information already reported by employers, banks, and other institutions. If everything on it is correct, no action is needed. If something is missing or incorrect, such as an eligible deduction that was not applied automatically, the taxpayer must correct and submit it by the deadline stated on the return, which varies by individual.
Deductions Applied Automatically
A flat €750 deduction for income-production expenses (such as tools or professional literature needed for work) is applied automatically, without any claim needed. If your actual expenses were higher than €750, you need to file the full amount yourself, with supporting documentation kept on hand.
A Deduction That No Longer Exists: Home Loan Interest
Home loan interest on a primary residence has not been deductible since 1 January 2023. This is a significant change from older guidance, which described interest as partly deductible from capital income. Banks still report interest paid to the Tax Administration, and it may still appear on a pre-completed return, but it is shown for information only and does not reduce tax. The one exception is interest on a loan used to buy a rental property, which remains deductible as it relates to income production.
Deductions That May Need to Be Claimed
A number of common deductions are not always applied automatically and are worth checking on a pre-completed return, including:
- Commuting costs between home and work, above a yearly threshold
- The household expense deduction (kotitalousvähennys), for renovation, care, or domestic help paid to a company or private person
- Work-related expenses above the automatic €750 threshold
Because the exact euro thresholds and percentages for these deductions are adjusted almost every year, the most reliable source for the current figures is the Finnish Tax Administration’s own deduction pages, such as Deductions for individuals on vero.fi.
Key Takeaways for 2026
- Corporate returns are still due four months after the financial year ends, using Form 6B.
- The automatic income-production expense deduction for individuals is now €750.
- Home loan interest on a primary residence is no longer deductible at all.
- Deduction thresholds change often, so always check current figures on vero.fi before filing.
Get Your Finnish Tax Return Right With Leinonen
Tax rules and deduction limits in Finland change frequently, and it is easy to rely on outdated information. Leinonen Finland’s accounting specialists keep track of these changes and can help your business or your Finnish tax affairs stay correctly filed. Contact Leinonen Finland to make sure your next return is accurate.
