Tax returns in Czechia: deadlines and obligations

A tax return is the annual reckoning with income tax — a company or sole trader states the tax base, claims costs and reliefs and works out how much they owe the state or how much the state will refund. It sounds simple, but several deadlines and follow-up obligations revolve around the return, and missing them costs money.

The key point is that there is not just one filing deadline — it depends on whether you file on paper, electronically, or an adviser prepares the return. The return is also linked to overviews for the insurers and possible tax advances. Let's go through it in order.

Who must file a return

A legal person (for example an s.r.o.) files a tax return for every taxable period, even if it was in a loss. For individuals the obligation depends on income: a sole trader files it, as does anyone who had income other than merely employment above the statutory limit. An employee whose tax was settled by the employer through an annual reconciliation and who had no further income need not file a return. If, however, they want to claim deductions or had several sources of income, they file the return themselves.

The filing deadlines

The basic deadline is by 1 April if you file the return on paper. If you file it electronically, the deadline extends to 1 May. And if a tax adviser prepares your return or the company is compulsorily subject to audit, it moves to 1 July. Filing electronically thus gives an extra month simply by filing online.

Watch out for one thing: companies and people who have a data box set up must file the return electronically as a matter of obligation. Because a data box is set up automatically for companies and many sole traders, the paper deadline of 1 April effectively does not apply to them and the earliest applicable one is 1 May.

Sole traders' overviews and tax advances

Sole traders also file, alongside the tax return, overviews for the social security administration and the health insurer — usually about a month after the return's deadline. From 2026 these overviews are filed electronically. On their basis a surcharge or overpayment on contributions is worked out and a new level of advances is set.

Depending on the last known tax liability, advances on tax may arise, payable during the year. Someone whose last tax was up to CZK 30,000 pays no advances. With tax from CZK 30,000 to CZK 150,000, semi-annual advances of 40 % are paid (due on 15 June and 15 December), and with tax over CZK 150,000, quarterly advances of 25 %. The advances are then offset against the tax in the next return.

Penalties and corrections of the return

If you file the return late, a penalty of 0.05 % of the tax for each day of delay applies, but no more than 5 % of the tax or CZK 300,000. There is a tolerance of five working days — within it no penalty applies, which gives a little room at a tight deadline.

An error in the return can be corrected in two ways. If you discover the error before the deadline expires, you file a corrective return, which fully replaces the original. If you discover it after the deadline, you file a supplementary return and pay any difference in tax. Admitting an error yourself is almost always more advantageous than waiting for an inspection to reveal it.

Conclusion

Remember three dates — 1 April on paper, 1 May electronically, 1 July with an adviser or audit — and that with a data box you file electronically as a matter of obligation. Alongside the return, keep sole traders' overviews and possible advances in mind. What rates and obligations apply to an s.r.o. is covered in the article corporate income tax for an s.r.o..

Frequently asked questions