Penalty for Late Tax Return: How Much Will You Pay
The tax return deadline is approaching and you realize you're not going to make it. Or you've already missed it and now you're wondering what the consequences will be. The penalty for filing a tax return late follows precise rules set out in the Tax Code, and the amount depends on how long you're overdue and how much tax you owe. In this article, we'll break down exactly how the penalty is calculated, what other sanctions you may face, and what you can do to minimize the fallout.
Key filing deadlines for the 2025 tax year
- 1 April 2026 – paper filing (only for those without a data mailbox)
- 4 May 2026 – electronic filing (mandatory for OSVČ with a data mailbox)
- 1 July 2026 – filing through a tax advisor
Any outstanding tax balance is also due on the same date.
How the late filing penalty is calculated
The penalty for late tax declaration is governed by Section 250 of Act No. 280/2009 Coll., the Tax Code. The calculation works as follows:
Basic formula
| Situation | Rate per day of delay | |---------|----------------------------| | Tax return with tax liability (you owe tax) | 0.05% of the assessed tax | | Tax return showing a tax loss | 0.01% of the reported tax loss | | Tax return with an excess deduction (VAT) | 0.05% of the assessed deduction |
Important rules for the calculation
1. Five-day grace period (penalty-free window)
The penalty only starts accruing from the 6th working day after the deadline has passed. The first 5 working days of delay are penalty-free. So if the electronic filing deadline is Monday 4 May 2026 and you file on Monday 11 May 2026, you're still within the penalty-free window.
Note: Working days apply
The five-day grace period is counted in working days, not calendar days. Weekends and public holidays don't count. However, once the grace period ends, the penalty itself is then calculated for every calendar day of delay (including weekends).
2. Maximum penalty cap
The penalty cannot exceed:
- 5% of the assessed tax, reported loss, or assessed deduction
- 300,000 CZK (absolute maximum regardless of the tax amount)
3. Minimum threshold
- The minimum penalty is 500 CZK
- If the calculated penalty is less than 1,000 CZK, the tax office automatically waives it (i.e., you pay nothing)
4. Penalty for not filing at all
If you don't file a tax return at all and the tax office has to formally request that you do so, the penalty is calculated the same way but continues to accumulate until you file (subject to the 5% / 300,000 CZK cap).
Practical penalty calculation examples
Example 1: Minor delay – 15 calendar days
Situation: An OSVČ was required to file electronically by 4 May 2026 but filed on 19 May 2026. Assessed tax: 45,000 CZK
Calculation:
- First 5 working days (5–11 May) = grace period, no penalty applies
- Days of delay for penalty calculation: 19 May − 12 May = 8 days
- Penalty: 45,000 × 0.05% × 8 = 180 CZK
Result: The penalty is less than 1,000 CZK, so the tax office waives it. The OSVČ pays nothing.
Example 2: 2-month delay
Situation: An OSVČ was required to file electronically by 4 May 2026 but filed on 4 July 2026. Assessed tax: 120,000 CZK
Calculation:
- Number of days of delay (from the 6th working day): approx. 56 days
- Penalty: 120,000 × 0.05% × 56 = 3,360 CZK
- Maximum check: 5% of 120,000 = 6,000 CZK → penalty does not exceed the cap
Result: The OSVČ pays a penalty of 3,360 CZK.
Example 3: Failure to file – penalty reaches the maximum
Situation: An OSVČ did not file at all. The tax office assessed tax of 250,000 CZK. Period of delay: More than 100 days.
Calculation:
- Penalty: 250,000 × 0.05% × 100 = 12,500 CZK
- Maximum check: 5% of 250,000 = 12,500 CZK → penalty has reached the 5% cap
Result: The penalty is capped at 5% of the tax = 12,500 CZK.
If the tax were higher — say 7,000,000 CZK — then 5% would be 350,000 CZK, but the absolute cap of 300,000 CZK would apply.
Example 4: Return showing a tax loss
Situation: An OSVČ filed their return 45 days after the deadline. The return shows a tax loss of 200,000 CZK.
Calculation:
- Number of days of delay (from the 6th working day): approx. 38 days
- Penalty: 200,000 × 0.01% × 38 = 760 CZK
Result: The penalty is less than 1,000 CZK → the tax office waives it.
Even though no penalty arises, filing late still causes complications — you cannot submit the earnings reports to the Czech Social Security Administration (ČSSZ) and your health insurance provider, as these are based on your filed tax return.
Late payment interest for overdue tax
The penalty for late filing is one thing. A second — and often more costly — sanction is late payment interest for overdue tax. This applies even if you file your return on time but pay the tax late.
How late payment interest is calculated
Late payment interest is governed by Section 252 of the Tax Code and is set at:
Czech National Bank (ČNB) repo rate on the first day of the calendar half-year + 8 percentage points
| Period | ČNB repo rate | Late payment interest (repo + 8 p.p.) | |--------|---------------|----------------------------------| | H1 2026 | 3.50% | 11.50% p.a. |
Late payment interest accrues for each day of delay, starting from the 5th working day after the tax due date (the first 4 working days are penalty-free).
Example: Late payment interest over 3 months
Situation: An OSVČ has a tax due date of 4 May 2026. The tax of 85,000 CZK is not paid until 4 August 2026.
Calculation:
- Number of days of delay: approx. 92 calendar days (from the 5th working day after the due date)
- Daily rate: 11.50% / 365 = 0.0315% per day
- Interest: 85,000 × 0.0315% × 87 days (after deducting the grace period) = 2,329 CZK
Add to this any penalty for late filing if the return was also submitted late.
Sanctions stack up
Sanctions accumulate. If you file your return late and also pay your tax late, you'll owe:
- Penalty for late tax declaration (0.05% per day of the assessed tax)
- Late payment interest for overdue payment (repo rate + 8 p.p.)
- Potentially a 20% surcharge if the tax office itself assesses additional tax (e.g., following an audit)
These three sanctions can run simultaneously and each is calculated independently.
Penalty for filing in the wrong format
Since 2023, virtually all OSVČ are required to file their tax return exclusively in electronic form (via data mailbox or the MOJE daně portal). If you file a paper return anyway, you face a 1,000 CZK penalty for breaching the electronic filing obligation.
This penalty is applied automatically and is independent of any penalty for late filing — you can receive both at the same time.
How to minimize sanctions
If you've missed the deadline or know you're going to, there are several strategies to limit the financial impact.
1. Use the 5-day grace period
The first 5 working days after the deadline are penalty-free. If the electronic filing deadline is 4 May 2026, you can still file without a penalty up to 11 May 2026.
2. File as soon as possible
The penalty grows every day. The sooner you file, the lower it will be. Don't sit on it — submit your return the moment it's ready.
3. Pay your tax as soon as possible
Late payment interest accrues daily. Even if you file late, pay your tax as soon as you can — ideally even before submitting your return. The tax office will correctly allocate the payment.
4. Consider a tax advisor
If you know you won't make the standard deadline, there's an elegant solution: grant power of attorney to a tax advisor before the standard deadline expires (e.g., by 4 May 2026). This automatically extends your deadline to 1 July 2026. Bear in mind — the power of attorney must reach the tax office before the original deadline passes.
Tip: A tax advisor as a last resort
If it's, say, 2 May 2026 and you know you won't be able to file by 4 May, you can:
- Enter into an agreement with a tax advisor
- Deliver the power of attorney to the tax office (via data mailbox this is instant)
- Gain time until 1 July 2026
This is a fully legitimate approach that can save you from a penalty. A tax advisor typically charges a few thousand CZK, which is often less than the penalty and late payment interest combined.
5. Request a penalty waiver
If you have serious reasons for the delay, you can ask the tax office to waive the penalty. The law allows for a waiver of up to 75% of the late declaration penalty.
How to request a penalty waiver
A waiver request is submitted to the tax office that issued the penalty. The procedure is governed by GFR Directive D-58 (from the General Financial Directorate).
When a request is likely to succeed
When deciding on a waiver, the tax office primarily considers:
📊Grounds for penalty waiver
How to submit the request
📋Steps to request a penalty waiver
Important: Administrative fee
Filing a waiver request for a penalty exceeding 3,000 CZK requires an administrative fee of 1,000 CZK. For penalties up to 3,000 CZK, the request is free of charge. The fee is payable regardless of the outcome.
All sanctions at a glance
📊Complete overview of sanctions under the Tax Code
Special situations
Late submission of earnings reports to ČSSZ and health insurance providers
In addition to the tax return itself, you are required to submit earnings and expenditure reports to the Czech Social Security Administration (ČSSZ) and your health insurance provider. Late submission of the ČSSZ report can result in a fine of up to 20,000 CZK. Health insurance providers can also impose a fine of up to 50,000 CZK for late submission of their report.
Late payment of insurance top-ups
If, after submitting your earnings report, you find you owe additional social or health insurance contributions, you must pay the outstanding amount within 8 days of submitting the report. Late payment attracts a penalty of 0.0333% of the outstanding amount per day of delay (for ČSSZ) and 0.0411% per day (for health insurance providers).
A real-world scenario — what happens if you don't file at all
If you don't file a tax return at all:
- The tax office will formally request that you file — it will set a substitute deadline
- If you still don't respond, the tax office will assess your tax ex officio based on its own data (Section 145 of the Tax Code)
- A late declaration penalty will be added to the assessed tax (as described above)
- Late payment interest will also accrue on the retrospectively assessed tax from the original due date
- If the tax office has to assess the tax itself, a 20% surcharge will be added on top
Frequently asked questions (FAQ)
Will I get a penalty for being just one day late?
No. The law provides a 5-working-day grace period. If you file within 5 working days of the deadline, no penalty will be issued. Note, however, that this grace period does not apply to tax payments — your tax should reach the tax office's account by the due date (though there is also a 4-day grace period for payments).
Can I extend my deadline?
You cannot directly request a deadline extension. However, you do have the following options:
- File electronically — you automatically get a one-month extension (4 May instead of 1 April)
- Appoint a tax advisor — your deadline extends to 1 July 2026
- Apply for a deadline extension (Section 36 of the Tax Code) — in exceptional circumstances, the tax office may grant an extension of up to 3 months
Can a penalty be offset against a tax refund?
Yes. If your return results in a refund and you've also been issued a penalty, the tax office will automatically offset the penalty against the refund. You'll therefore receive a smaller refund.
What if I pay my tax on time but file my return late?
You will still incur a penalty for late tax declaration (0.05% per day). However, paying the tax on time means you won't owe any late payment interest — that only applies to overdue payments. The overall financial impact is therefore significantly lower.
Does the five-day grace period apply to electronic filing too?
Yes. The 5-working-day grace period applies to all filing methods — paper, electronic, and through a tax advisor. It always runs from the relevant statutory deadline.
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Official sources and links
- Czech Financial Administration – general information on personal income tax
- Act No. 280/2009 Coll., Tax Code – Section 250 (penalty for late tax declaration)
- Act No. 280/2009 Coll., Tax Code – Section 252 (late payment interest)
This article serves as a general informational guide and does not replace individual tax advice. The information is accurate as of the date of publication (February 2026) and is based on currently applicable legislation. The late payment interest rate may change depending on the ČNB repo rate. For advice on your specific situation, please consult a qualified tax advisor.
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