How to request adjustment of prepayment?
The amount of your prepayments is based on an estimate of taxable profits for the year. If actual income or actual expenses are different from the estimated income and expenses, we recommend that you change your prepayments. You can make the changes in MyTax until tax assessment is completed. You can look up the end date for tax assessment on your tax decision.
For individual taxpayers, the Tax Administration completes assessment at a date that falls between May and October.
In the case of a corporate entity, the Tax Administration completes assessment before 10 months have elapsed after the end of the final calendar month of the accounting year of the corporate entity.
Guidance for using MyTax
Individuals: How to request adjustment of prepayment in MyTax