The tax year runs from 1 January to 31 December. The tax liability of a foreign resident begins from the day that person moves to Finland and ends when that person moves out of Finland. Basically, the same tax rules apply for a full year of residency as for part of a year of residency.
Spouses file separate returns; joint filing or income splitting is not possible.
In most cases, individuals receive pre-completed tax returns in April of the year following the tax year. The due date is in mid-May; however, if there is no information to be added or corrected, it is not necessary to return the pre-completed tax return to the tax authorities.
Non-resident individuals generally do not file any tax return because the final tax is withheld at source from their Finnish-source income. However, for taxable income not subject to the tax at source withholding (e.g. rental income taxable in Finland), a tax return must be filed in accordance with the normal procedure.
Payment of tax
Income tax shall be withheld from salaries and most other types of income (e.g. pensions, other remuneration for work than salary, and dividends paid by publicly quoted Finnish companies).
Generally, if individuals receive income not subject to withholding (e.g. salary paid abroad by a foreign entity having no PE in Finland), they are required to make monthly payments of estimated tax if they receive a preliminary tax bill from the tax authorities. Otherwise, they can consider whether to apply for a preliminary tax decision from the tax authorities or just report the income on the tax return and wait for the final tax bill. Interest is payable on residual tax.
Residual tax is assessed by the Tax Administration according to the filed tax return. The due dates vary but until the residual tax is assessed the individual may pay income taxes voluntarily to reduce the interest assessed on residual tax due. The due dates are visible on the taxpayer’s tax assessment (tax decision). Tax refunds are paid between August and December in the tax assessment year.