Tax Returns in 2026: Who Must File One, and What Are the Deadlines?

Are you unsure whether this requirement applies to you, or are you dealing with complex income issues, an audit, or a dispute with the tax office? As part of our tax advisory services, we’ll assess your specific situation and recommend a legally sound course of action.

What deadlines should you expect this year?

The basic deadline for filing your 2025 tax return is April 1, 2026. However, if you’re filing electronically and can’t meet this deadline, you still have until May 4, 2026. This typically applies to most self-employed individuals who are required by law to have a data box and must therefore file their returns electronically. If a tax advisor or attorney files your return on your behalf after the basic deadline, the deadline is extended to July 1, 2026. The same deadline applies to taxpayers who are required to have their financial statements audited by a certified public accountant. However, there’s nothing stopping you from ignoring the deadlines and preparing your tax return as early as February or March.

How do I fill out my tax return?

The first option is to fill out and file your tax return online through the MOJE daně portal. You can log in, for example, using your bank ID, a chip-enabled ID card, or your data box login credentials. You can also prepare your return in another application and then submit it via a data box. If you have access to a data box established by law and are filing a business-related tax return, you must submit it electronically in the prescribed format and structure.

However, it is important to distinguish between the method of submission and the method of processing. While the tax authority’s online form is sufficiently clear and intuitive for some members of the public—who find it sufficient on its own—others would welcome more assistance. In that case , you can use various apps and paid services that help with taxes. One such service is onlinepriznani.cz, which, for a relatively low fee (in the range of a few hundred crowns), guides you through the entire process, clearly and in plain language explaining what needs to be filled out where, where to obtain the relevant information, and what the limits are for deductible items, donations, and so on. And, of course, it also calculates everything and fills in the results, including any overpayments or underpayments to the health insurance company and the Social Security Administration. This means that even those who don’t fully understand the language of laws and numbers can successfully file a complete tax return.

For those who do not want to deal with tax returns at all (and do not have an employer who is legally required to process their taxes), the only option is to use the services of a tax advisor. As we mentioned above, in such a case, the filing deadline will be significantly extended.

Who is required to file a tax return?

The obligation to file a tax return does not automatically apply to every self-employed person or business owner. Generally, you must file a return if your annual taxable income exceeds 50,000 crowns. You must also file a tax return if you did not reach this amount but are reporting a tax loss. The same rules apply to retirees, students, or parents on maternity or parental leave if they also run a business or have other taxable income. An exception may apply, for example, to self-employed individuals under the flat-rate tax regime—if they meet all the conditions and their tax equals the flat-rate tax, they generally do not file a tax return.

If you are an employee, a slightly different system applies to you. If you received income during the year from only one employer or sequentially from several employers and signed a “pink declaration” with all of them, you generally do not need to file a tax return. However, this changes if you have other taxable income in addition to your employment (such as from a business or rent) and the total for 2025 exceeded 20,000 korunas. Income that is tax-exempt or income from which tax has already been withheld is not included in this limit.

If you are not required to file a tax return, you can ask your employer for an annual tax settlement. This is usually worth doing, because while some tax credits and deductions can be claimed throughout the year (such as the child tax credit), others can only be claimed once a year (mortgage interest, charitable donations, or blood donations). As a result, you may end up receiving a refund from the government.

If, as an employee, you are not required to file a tax return and do not request an annual tax settlement, then your tax obligation is fulfilled by the monthly tax withholdings.

An Example from Our Law Firm’s Practice

From our experience, we know that when it comes to rental income, a common question is which expenses can actually be claimed and whether it is more advantageous to use a flat-rate deduction or to claim actual expenses. For example, we handled a case involving a client who needed to prepare a tax return for his mother. She was renting out an apartment and wanted to correctly report her rental income while also claiming all the expenses that the law allowed her to deduct.

First, we reviewed the lease agreement, the statement of rent received, and the receipts for expenses related to the apartment. We separated the items that could be included as tax-deductible expenses from payments that, while related to the property, could not be claimed for tax purposes. At the same time, we compared the 30% flat-rate expense deduction with the actual expenses. In this case, the actual expenses proved more advantageous, so we chose this option and used them to calculate the tax base for rental income.

We then prepared a complete individual income tax return, verified the consistency of the individual amounts, and explained to the client the basis for the resulting tax liability. Thanks to the correct deduction of expenses, we were able to reduce the tax base compared to a scenario where the calculation would have been based solely on rental income. This case also demonstrated that it is not always advantageous to automatically opt for the flat-rate expense deduction when renting— when higher verifiable expenses are involved, actual expenses may be significantly more beneficial.

Who is not required to file an income tax return?

Conversely, this obligation does not apply to those

• whose annual taxable income did not exceed 50,000 crowns and who do not report a tax loss,
• who are employees and received income only from one employer or successively from multiple employers, signed the pink declaration with all of them, and whose other taxable income did not exceed a total of 20,000 crowns,
• those who received only tax-exempt income throughout the entire year—typically sick pay or unemployment benefits.

Income from abroad, for example, must be assessed separately, as it depends on the specific double taxation treaty and the way in which foreign income is taxed in the Czech Republic.

However, it is sometimes advantageous to request an annual tax settlement because certain deductions and tax credits cannot be claimed during the year. For this reason, an employee may be entitled to a tax refund as a result of the annual tax settlement.

The situation can quickly become complicated if you combine employment with running a business, rental income, investments, or income from abroad. It’s not always clear at first glance whether income is taxable or exempt, or whether you’re already required to file your own tax return. If you’re unsure, we can assess your situation as part of our tax legal advisory services and recommend the correct next steps before the issue reaches the tax authority.

When and where should you pay your income tax?

Most self-employed individuals now file their tax returns electronically, and if they do not file by the initial deadline, they have until May 4, 2026, to do so. But be aware of one small detail: if you decide to get your taxes out of the way early and file your return by April 1, 2026, you must also pay any outstanding balance by that same date. So, for example, if you file your return electronically on March 20, you cannot wait until May to make the payment.

If you file your electronic return after April 1, you have until May 4, 2026, to both file and pay your taxes.

You may be granted an even longer extension if a tax advisor or attorney is preparing and filing your tax return on your behalf. If they file it after the initial April deadline, the deadline for both filing the return and paying the tax is extended to July 1, 2026.

The amount due can be paid, for example, by bank transfer, postal money order, or at a tax office cashier’s window. You can find the account numbers on the Financial Administration’s website; be sure to pay special attention to using the correct variable symbol. For individuals, this is usually the birth number without a slash. When making a non-cash payment, you may enter the constant symbol 1148, though this is not required.

If you are late in paying your taxes, late payment interest begins to accrue on the fourth day after the original due date. Interest does not apply to a three-day delay, but it is definitely not a good idea to rely on this “buffer” when paying taxes.

If you have any outstanding health and social insurance payments, be aware of the eight-day deadline. Any underpayment must be paid no later than 8 days after the date on which the relevant statement was or should have been filed. Therefore, if you file the statement late, this does not automatically extend the due date for the underpayment.

Starting in 2026, self-employed individuals can also expect one practical change regarding health insurance—the report for the health insurance company must now be filed exclusively electronically. For social insurance, mandatory electronic filing applies primarily to self-employed individuals who have access to a data box established by law.

Summary

The 2025 tax return must be filed by April 1, 2026, as the standard deadline; by May 4 for late electronic filing; and by July 1 if the conditions for filing through a tax advisor or attorney are met or if a mandatory audit is required. The calculated tax is also due by the same deadline.

The obligation to file a tax return depends primarily on the type and amount of income. The general threshold is 50,000 CZK in taxable income; for employees, additional income under Sections 7 through 10 exceeding 20,000 CZK may trigger the need to file a return. Special rules apply, for example, to the flat-rate tax regime or foreign income. If you have missed any of the deadlines or are unsure about the correct tax regime for your income, it is best to address the situation without delay.