How many years back can I file?

Missed a tax return, forgot the social and health overviews, or never claimed a refund? In the Czech Republic you can usually still sort out the last three years. This guide explains the time limits, what a late return costs, and what to do about missed overviews.

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.

With a trade license: the overviews too

For each year you were self-employed with the 60/40 or real-expense method, there are three documents: the tax return, the overview for social security (přehled pro ČSSZ) and the overview for your health insurer. Missed the tax return? Then you almost certainly missed the overviews as well, and those count separately.

• File the missing overviews for every year, together with the late tax return. Without them the offices do not know your real income: they can set your premiums themselves, usually higher, and they can fine you for not filing. [check fine amounts]
• Time limit: unpaid social security and health insurance premiums can be claimed for 10 years from their due date. That is much longer than for income tax, so a missed year with a trade license does not simply go away after three years.
• Late payment costs penále on social security and health insurance from the original due date: for social security the repo rate plus 8 percentage points a year; for health insurance a daily rate set the same way (0.0329% a day for debts from 2025). [check]
• Pay what you owe with the variable symbol you already use for your monthly payments, so the payment is matched to the right year.

Flat-tax method years (paušální daň): if you were in the flat-tax method for the whole year and stayed within its limits, there was no tax return and no overviews for that year. What can be missing are monthly flat-tax payments, and those are debts with each of the three offices. If you left the flat-tax method during the year or went over its limits, you file a normal tax return and overviews for that year.

See the 3 accounting methods and the social and health minimums for how the amounts are calculated.

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. [check]
• 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.

Work out the interest for a late payment with the late payment interest calculator.

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.

This is general information, not advice for your own situation: older years often have their own complications, such as a visa, a move abroad or income from abroad.

Related

• Income tax return filing service, also for earlier years
• After filing: what to pay and when
• The personal income tax return
• Late payment interest calculator

Official sources: Tax Code (Act No. 280/2009 Coll.) §§ 141, 148, 250 and 252, zakonyprolidi.cz; Act No. 589/1992 Coll. on social security premiums and Act No. 592/1992 Coll. on health insurance premiums; financnisprava.gov.cz, cssz.cz.