Back taxes – individual taxpayers

We collect information that affects your taxation from your previous year's tax card and from employers, pension institutions and banks, for example. Based on this information, we create a pre-completed tax return for you in MyTax by the end of March. 

Check the information on the tax return. If all the information is correct, you do not need to do anything.

If you make corrections, the filing deadline is 1, 14, 21 or 28 April 2026. You can check the due date on your tax return and in MyTax. The corrections you have made to your tax return in MyTax must arrive at the Tax Administration by 23:59 on the due date stated in your return. The paper forms for corrections must arrive by 16:15 on the due date printed on your return.

Making corrections in MyTax or on paper

Based on your pre-completed tax return and the corrections you have made to it, the Tax Administration will calculate the total amount of taxes and charges. If your tax rate has been too high, you have paid too much tax and will get a tax refund. If your tax rate has been too low, you will have to pay back taxes.

If you did not make any changes to your pre-completed tax return, the tax decision and payment details you received in the spring will remain in force.

If you make corrections to your tax return, you will receive a new tax decision by the end of October. In that case, the payment date of your tax refund or the due dates of your back taxes may change. The payment dates may also change if your spouse makes corrections to their tax return.

Tax decision