Error in a tax return in Finland: how to correct it
An error in a tax return in Finland can be corrected in two ways. Until the tax assessment is completed, it is enough to submit new information in the return itself; after it is completed, you must file a request for adjustment, known as an oikaisuvaatimus.
The date on which the assessment is completed is shown in the tax decision in OmaVero. A request for adjustment may be filed no later than three years from the beginning of the year following the tax year. The longer you wait, however, the more slowly the matter is processed.
Our experience at International Law Firm "Zahist" shows that most overpayments arise not because the correction is complicated, but because people are unaware of this route. Below we explain how to correct a return, which time limits apply, and what to do about tax that must be paid.
Two ways to correct an error: before and after the assessment is completed
The method depends on whether the tax assessment has been completed. You can check this in the tax decision, which is available in OmaVero after the pre-completed return arrives.
| Situation | What to do |
| The assessment is not yet completed | Enter changes and additions directly in the return |
| The assessment is completed | File a request for adjustment (oikaisuvaatimus) |
| Information was filed late | Follow the separate instructions for a late return; additional payments may apply |
| Vero found the error | The Tax Administration may correct the assessment on its own initiative |
According to Vero, requests for adjustment take longer to process than returns. It is therefore better to correct an error in time, before the assessment is completed.
An error in a tax return: how to correct it before the assessment is completed
If you notice an error or missing information in the pre-completed return, simply enter the changes. This is the fastest and least expensive method.
You can also submit certain information in advance, for example travel expenses or rental income. The specific date on which the assessment is completed is stated in the tax decision, so use that date as your reference.
Request for adjustment (oikaisuvaatimus): when it is filed and what time limits apply
A request for adjustment is filed after the assessment is completed. It allows the assessment of income to be changed, as well as deductions, for example travel expenses or household expenses.
The time limit is three years from the beginning of the year following the tax year. According to Vero, for tax year 2023 the deadline expires at the end of 2026, for 2024 at the end of 2027, and for 2025 at the beginning of January 2029.
| Tax year | Last day for filing the request |
| 2023 | 31 December 2026 |
| 2024 | 31 December 2027 |
| 2025 | 2 January 2029 |
Dates may be postponed when the last day falls on a weekend. A request filed through OmaVero must arrive by 23:59, while a paper request must arrive earlier, before the end of the business day.
How to file an oikaisuvaatimus step by step
The primary route is electronic. A paper form or a free-form request may be used only if access to OmaVero is not possible.
- Log in to OmaVero and open the tax matters tab
- Find the section on requests for adjustment and select the type “individual income tax”
- Select the relevant tax year
- Select the return to which you wish to file the request
- Complete the fields that require a change and add an explanation
- Submit the request and track its status in the service
After the review, the decision will arrive in OmaVero. It will state whether you are entitled to a tax refund or must make an additional payment.
What to do about tax before the decision: payment and suspension of collection
Filing a request does not cancel the obligation to pay the tax by the due date. If you have a residual balance, it must be paid; otherwise, late-payment interest will accrue.
- Pay the tax by the payment date even after filing the request
- If payment is difficult, apply for an instalment plan
- You may request that enforcement collection be suspended while the matter is under review
- Late-payment interest continues to accrue during the suspension
- If the request is granted, any amount overpaid is refunded with interest
Suspension of collection may be full or limited. You should therefore read the conditions carefully and not rely solely on general advice.
When Vero corrects an assessment on its own and what to do if you disagree
The Tax Administration may also correct an assessment after it has been completed if it receives new information. This may result in either a refund or an additional payment.
The time limit for such a correction is generally the same as for your request. However, a request for adjustment may be filed for at least 60 days after the decision is received.
| Event | What you can do |
| Vero corrected the assessment on its own | File a request for adjustment if you disagree |
| The request for adjustment was rejected | Appeal the decision to the administrative court |
| The time limit was missed | Seek a legal assessment of possible exceptions |
A decision on a request for adjustment may be appealed to the administrative court. The time limits and procedure are set out in the appendix to the decision.
Example: how the assessment completion date determines the method of correction
Vero gives an illustrative example. A person receives a pre-completed return for 2025 in the spring and believes the information is correct, so makes no changes. Later, the person notices an error in travel expenses.
The tax decision states that the assessment is completed on 17 June 2026. If the error is found before that date, it is enough to submit new information in the return; if it is found afterwards, a request for adjustment is required.
| When the error is found | Method of correction |
| Before 17 June | New information in the return, a simpler and faster route |
| After 17 June | A request for adjustment; processing takes longer |
This example shows why it is important to know your completion date. The same omission can be corrected in a few minutes, or you may wait weeks for a decision.
A late return: are there additional payments
If you file information late, the Tax Administration may impose additional sanctions. Vero treats this separately: it concerns a late-filing fee and a tax increase.
- Check whether the assessment has not yet been completed, as this determines the procedure
- Submit the missing information as soon as possible, without waiting for a reminder
- Gather an explanation of the reasons for the delay if they were objective
- Check whether mitigation of the sanctions is available in your situation
- Do not ignore letters from the Tax Administration
The exact amounts and conditions depend on the specific case, so do not rely on approximate figures from forums. It is better to check Vero’s instructions or obtain a legal assessment.
Which documents to prepare so that the correction is accepted
Even a correctly drafted request may be rejected if it is not supported by documents. Gather in advance everything that proves your position.
| Type of change | What to prepare |
| Travel expenses | Contracts, tickets, route calculations |
| Household expenses | Invoices, contracts, proof of payment |
| Foreign income | Certificates of income and taxes paid abroad |
| Rental income | Lease agreement, proof of payments and expenses |
| Employer’s error | Payslips, employer’s letter with the correction |
Typical mistakes that lead to a late correction of the return
Below are the mistakes that occur most often. All of them can be corrected, but it is better not to make them in the first place.
- Not checking the pre-filled return and hoping that everything is correct
- Not knowing the assessment completion date and missing the convenient window for changes
- Filing a request for reconsideration when it would have been simpler to correct the return itself
- Not paying the tax before the decision, assuming that the application suspends payment
- Not attaching supporting evidence: receipts, contracts, statements
- Missing the final deadline for the application, especially for earlier years
Each of these mistakes can lead to unnecessary interest or the loss of the right to a refund. A calm review of the documents helps avoid this.
Why correcting a return on your own can be difficult
At first glance, it seems enough to click a few buttons in OmaVero. In practice, however, a person faces a language barrier, complex wording, and different deadlines.
- Instructions are in Finnish or Swedish, and translations are often delayed
- It is hard to understand until when an action can be taken in the simplest way
- It is unclear which documents to attach so that the application is granted
- It is difficult to account for foreign income and taxes paid abroad
- A refusal or silence from the tax authority requires knowledge of the appeal procedure
That is why Ukrainians are increasingly turning to lawyers. The question of how to correct an error in a tax return has its own nuances in each case.
On your own or with International Law Firm "Zahist" : a comparison
The difference between the two approaches is best seen in a comparison.
| Parameter | On your own | With International Law Firm "Zahist" |
| Choosing the method of correction | Based on general advice | Analysis of the assessment completion date and the situation |
| Documents | Risk of forgetting supporting evidence | A checklist and a completeness review |
| Deadlines | Easy to miss | Monitoring and reminders |
| Foreign income | Difficult to report correctly | Correct reporting and credit for taxes |
| Refusal or silence | Unclear what to do next | Request for reconsideration, appeal |
| Outcome | Depends on luck | A clear plan and oversight through to the outcome |
We do not guarantee decisions of public authorities, as the final word rests with them. However, proper preparation significantly reduces the risk of losing money.
How International Law Firm "Zahist" helps correct a tax return in Finland
We work according to a clear plan so that you always understand what is happening in your matter.
- Analysis of the situation: tax year, assessment completion date, type of error
- Review of the return and the tax decision, identification of discrepancies
- Selection of the most advantageous route: amending the return or filing a request for reconsideration
- Preparation of explanations, supporting documents, and filing
- Monitoring of deadlines, the status of the review, and payment of the tax
- Appeal of the decision if the application is rejected
- Further support on matters of filing, residency, and foreign income
At every stage, you know what is happening and are not left alone with the bureaucracy. This is especially valuable when significant amounts are involved.
Legal assistance with a tax return
Do not postpone the correction: the later you act, the harder it is to gather evidence and the fewer options remain. If the error is noticed in time, it can be corrected without a request for reconsideration.
Contact the lawyers of International Law Firm "Zahist" , and we will review your case and advise you on how to correct an error in a tax return as quickly as possible and with minimal losses.
