How Many Years Back Can I File a Czech Tax Return?

The short answer: about three years

The tax office can only set your tax within a fixed period, the lhůta pro stanovení daně (time limit for assessing tax). It is 3 years, counted from the original deadline of the tax return for that year. As long as that period is open, you can still file a return for the year, correct one, or claim a refund. Once it has passed, the year is closed: the tax office can no longer ask for tax, and you can no longer claim money back.

So at the end of 2026, the years 2023, 2024 and 2025 are still open. If your deadline for a year was later (for example 1 July because a tax advisor filed for you), the three years run from that later date. Do not wait for the last weeks: a return needs documents, and the tax office has to receive it in time.

When the period is longer: up to 10 years

The three years get longer in some cases. If, in the last 12 months of the period, the tax office starts a tax audit, sends you a request (výzva) to file or correct a return, or you file a supplementary return yourself, the period is extended by one year from that moment. In total it can never be longer than 10 years. In practice this means: if you never filed and the tax office finds out later, for example through the automatic exchange of information with other countries, an older year can still be opened.

Employees: refunds you can still claim

Many employees never file a tax return: the employer settles the year (roční zúčtování). But the settlement only happens when you ask for it and signed the tax declaration, and it does not cover everything. You can still claim, for every open year:

• tax credits the employer did not apply, for example for children or a spouse with low income, including the child tax bonus;
• deductions such as mortgage interest, pension and life insurance savings, or donations;
• the full yearly basic credit when you worked only part of the year, or had two employers one after the other.

See tax benefits for families and the tax refund estimate.

Forgotten income: rent, investments, income from abroad

A Czech tax resident declares worldwide income. Rent from a flat, a salary or pension from abroad, or the sale of shares or crypto that was not tax-free all belong in the return, and with other income above 20,000 CZK next to a salary you have to file. If you missed such income, file the return (or a supplementary return) for each open year. Income already taxed abroad is often largely or fully relieved by a double tax treaty, so the extra Czech tax can be small; see foreign income and double tax treaties.

Late filing: penalty and interest

Whether filing late costs you anything depends on whether you had to file.

• You did not have to file (for example an employee with only a Czech salary who now wants a refund): there was no deadline to miss, so a late return for an open year normally costs nothing extra.
• You had to file and did not: the late-filing penalty (pokuta za opožděné tvrzení daně) is 0.05% of the tax for each day of delay, counted after the first 5 working days, at most 5% of the tax and at most 300,000 CZK. A penalty below 1,000 CZK is not charged, and it is halved when you file within 30 days of the deadline and had no other delay that year. For a tax loss it is 0.01% a day.
• Tax paid late also costs late-payment interest (úrok z prodlení): the Czech National Bank repo rate plus 8 percentage points a year, for at most 5 years, from the fifth working day after the original due date. Interest of 1,000 CZK or less is not charged.

If the tax office has sent you a výzva and you still do not file, it can estimate your tax from the information it has (stanovení podle pomůcek), and the minimum penalty is then 500 CZK. Filing yourself before a výzva arrives is almost always the cheaper way.

How to file for an earlier year

1. Use the return form for that year: the rules, rates and tax credits of that year apply, not today's.
2. Collect the documents of that year: the employer's income confirmation (potvrzení o zdanitelných příjmech) for each employer, proof of children, mortgage interest or pension savings, and statements for income from abroad.
3. Convert foreign income with the exchange rates of that year (the single yearly rate or the daily ČNB rates).
4. Ask for the refund on the return itself (the last page has a request for the overpayment, with your bank account).
5. Did you already file, but the return was wrong? Then you file a supplementary return (dodatečné daňové přiznání). If you owe more tax, it is due by the end of the month after the month you found the mistake; if you paid too much, you may file it any time while the year is open.

Companies (s.r.o.)

The same three-year period applies to the corporate income tax return of an s.r.o., with the same penalties and interest. A company that missed years usually also has bookkeeping to catch up and financial statements to publish in the Collection of Deeds (Sbírka listin), which is a separate obligation. See every obligation of an s.r.o. and the company tax return.

This is general information, not advice for your own situation.

Related

• Personal income tax return, also for earlier years
• Do I have to file a Czech tax return as an employee?
• Tax refund estimate
• Investments, ETFs, crypto and RSUs in your tax return

Official sources: Tax Code (Act No. 280/2009 Coll.) §§ 141, 148, 250 and 252, zakonyprolidi.cz; financnisprava.gov.cz.