When you log in to MyTax, your tax-related letters will change from paper to electronic form automatically. Read more about the changes.
You can file and pay self-assessed taxes (such as value-added tax or lottery tax) in MyTax. Tax returns on self-assessed taxes must be filed electronically. Filing on paper is allowed only in exceptional cases.
Choose how to submit
Log in to MyTax and select Tax matters on the home page. Next, select Self-assessed taxes.
You can submit the information electronically, for example:
- via an API
- by uploading a file to the Ilmoitin.fi e-service.
You can file the return on paper only for a special reason, for example if electronic filing is not possible because of technical failure.
If you submit the details on paper, select the correct form:
Form for 2026: Use this form if you are reporting details for the tax period 1/2026 or for later tax periods.
Form for 2025: Use this form if you are reporting details for tax periods in 2025.
Form for 2024: Use this form if you are reporting details for tax periods that end no later than 31 December 2024. Also use this form if you are applying retroactively for VAT relief at the lower limit.
Download the form
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The online authorisation mandate
You can use the Suomi.fi Authorization to enable you to deal with taxes for another person – including legal persons, companies, other entities – through e-services, over the telephone, or by visiting a service point on their behalf.
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Letters of authorisation on paper
You can receive a letter of authorisation written in the name of a company, to manage a single tax-related issue. If you – either personally or for an organisation that had been authorised – submit tax-related information on paper, a copy of the letter of authorisation has to be enclosed. A letter of authorisation does not provide access to MyTax.
Power of attorney for managing the taxes of a company (3804)
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Note: Although excise duties are self-assessed taxes, they are not filed on Form 4001. Read the instructions for filing and paying excise duty.
VAT instructions
New VAT rate from 1 September 2024, instructions for VAT reporting
Key terms:
The Tax Administration can use automated decision-making in the context of resolving tax matters. This means that a decision concerning your tax matter may be based on partial or full use of an automated decision-making system. Read more about automated decision-making at the Tax Administration (only in finnish).
Page last updated 6/10/2026