When you log in to MyTax, your tax-related letters will change from paper to electronic form automatically. Read more about the changes.
Individual taxpayers, self-employed individuals, agricultural and forestry operators, general partnership and limited partnerships: claim adjustment of your income tax primarily in MyTax. If you cannot use MyTax, you can claim adjustment with a paper form or by submitting a free-form claim on paper. You can also authorise another person to act on your behalf.
Choose your filing method
Claim for adjustment in MyTax.
See the instructions for filing a claim for adjustment in MyTax
If you file a claim for adjustment on paper, remember to add the required enclosures stated in the instructions for filling in the form. Send the form and enclosures to the address given on the first page of the claim for adjustment form.
Download the form
If you file a free-form claim for adjustment, make sure to state:
- the name and personal identity code of the individual claiming adjustment (or the Business ID in the case of business partnerships)
- the tax year that your claim for adjustment concerns
- how you want the tax assessment to be changed
- on what grounds you are claiming adjustment.
If you submit a free-form claim, fill in and print Form 3308e (Claim for adjustment of income tax) and use it as a cover page. Send the claim to the address stated on the form. Also enclose any other documents you wish to refer to unless you have delivered them to the Tax Administration previously.
Huomio osio alkaa
The online authorisation mandate
You can use the feature called “Suomi.fi Authorization” to enable you to deal with another person’s taxes through e-services, over the telephone, or by visiting a service point on their behalf.
Huomio osio päättyy
Huomio osio alkaa
Letters of authorisation on paper
You can receive a letter of authorisation from the other person. It will enable you to deal with that person’s taxes on the telephone, by visiting a service point on their behalf, or by submitting information on paper tax forms. To have a letter of authorisation (often called a ‘power of attorney’) does not provide access to MyTax.
Letter of authorisation for tax representation of individual taxpayers (3818)
Huomio osio päättyy
Huomio osio alkaa
When is there no need for an authorisation mandate?
The following circumstances are examples of when you can deal with someone else’s taxes with no authorisation.
You have child younger than 18 and you handle the child’s taxes
You are automatically authorised to access MyTax for the child, without an authorisation. Log in to MyTax and select “Act on behalf of someone else”.
Read more about this subject on Suomi.fi
You are a guardian
You do not need a Suomi.fi authorisation when your continuing power of attorney for being a guardian is officially confirmed, or when you are registered as a private guardian. Log in to MyTax and select “Act on behalf of someone else”.
Note: If you are a public guardian, in other words, a public official employed by a public guardianship office, you can only use paper forms.
Huomio osio päättyy
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 4/2/2025