The 7 most common errors in tax returns. How to correct them?

Some mistakes are repeated in tax returns every year, even though the tax administration draws attention to them. Find out which ones - you'll increase your chances of getting your return right first time. Plus, we've prepared a guide on what to do if you've filed a return with an error.


  • Deadline for filing and paying tax. The key to success is to file your return on time. This year, file paper by April 1 and electronically by May 2. If a tax preparer or attorney prepares and mails your return for you, you have until July 1. You must also pay your tax by the same deadlines. So if you're filing at the last minute, make sure you send your payment in advance and that it's credited to the tax office's account on time.
  • Discount for children. The tax credit for a dependent child is always deducted on the return by one parent only. If you have more than one child, you can choose who gets the credit for which child - but you can't both claim the credit for one child at the same time.
  • Spouse discount. You are entitled to a credit of CZK 24,840 if the other person's income does not exceed CZK 68,000 per year. However, the income limit includes not only gross wages and business earnings, but also maternity, sickness, unemployment or old-age and disability pensions. Parental allowance is not included.
  • School fees. You can reduce your income tax by the cost of your child's stay in pre-school, up to a maximum of CZK 15,200 per year. However, if you paid less for preschool last year, you will claim the actual amount of the deduction, not the full amount.
  • Mortgage interest deduction. It can be applied up to a maximum of CZK 150,000 per year, and only if you are the owner of the property and use it for living purposes - either yourself or your relatives. You are not entitled to the deduction, for example, for a mortgage on a rental apartment or a holiday cottage.
  • Attachments. Are you claiming tax deductions for mortgage interest, life insurance, pensions or gifts? Don't forget to attach a receipt to your form to confirm that you actually paid them.
  • Signatures. When you file on paper, make sure you have signed both the tax return itself and the claim for a refund if it applies to you - they are two documents.

TIP: Do you invest and don't know whether to report your trading on your tax return? Read our articles on how to tax cryptocurrencies and how to tax stocks.


Sent. You were relieved to get this year's tax return done, but then you realised you made a mistake or forgot something when you filled it in.

What now? Don't worry, you have two ways to fix it.


You can use an amended return if the deadline for filing your tax return has not yet passed. Simply resend the form with the correct details, ticking the box on the first page to indicate that it is a corrected return. The tax office will then only take the new one into account and will not take the first one into account or impose a penalty.


Did you discover the error after the deadline? Then you are affected by the additional return and it depends on what the error is:

  • If you have forgotten to claim the allowance and your tax liability would be lower, it's up to you whether to start filling it in again.
  • If you should have paid more tax, you must file a supplementary return - the deadline is the end of the month following the month in which you discover the error. For example: you file an e-return in April and find out in May that you forgot to declare some of your income. You file a supplementary return by the end of June and do not face penalties. You will be affected if you do not meet the deadline or if the tax office finds out about the mistake before you send in the additional return. The amount of the penalty is set as interest on the difference between the tax you have declared and the tax you should have paid.

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