The deadline for submitting Czech personal income tax returns for the 2025 tax year is approaching.
Standard deadline: 1 April 2026
Electronic filing deadline: 4 May 2026 (extended because the usual May 1 date falls on a weekend/holiday timing)
Tax return filed via a tax advisor (based on a PoA): 1 July 2026
Below are the most common errors we still see every year and how to avoid them.
Most common errors when filing tax returns
🔸Wrong form or wrong filing method
If you are self-employed (OSVČ) and you have a mandatory data box, you generally need to file electronically.
Also, PDF uploads are not considered a valid electronic tax return. A correct submission must be sent in the required electronic format (typically XML) — the easiest way is through MOJE daně or databox.
🔸 Claiming deductions and credits incorrectly
A few frequent pitfalls:
Child tax credit can be claimed by only one parent.
Mortgage interest deduction can generally only be claimed by the owner of the property, and the property must be used for qualifying housing needs (typically your own permanent living, or in specific cases for close relatives as defined by law). Maximum deductible amount is CZK 150,000 (CZK 300,000 under certain conditions, mainly for older mortgages).
🔸Requesting a tax refund — missing steps
When filing, don’t forget the “refund mechanics”:
If you file electronically via MOJE daně / DIS+, no extra signatures are needed — authentication happens through your login. But you still need to fill out the tax refund request.
If you file on paper (less and less common in practice), the tax office often sees missing signatures in the refund section, which delays processing.
🔸Forgetting to report tax-exempt income over CZK 5,000,000
Even if you don’t need to file a tax return, you may still have a separate duty to notify the tax office if you received tax-exempt income exceeding CZK 5 million in 2025.
Common examples:
gifts and inheritances
sale of securities / shares / business interests
high-value gifted or inherited real estate (depending on the exemption type)
❗ Missing this notification can trigger significant penalties.
Practical tip (especially before 4 May 2026)
If you want to avoid last-minute stress, file electronically early through MOJE daně / DIS+ — and double-check the common errors above before submitting.
If you’re unsure whether you need to file, read our article or feel free to reach out.