How to File a Tax Return Online With an Electronic Signature?

Article content

The latest possible day for filing the income tax return for the 2025 taxation period is 31 March 2026. Obliged persons must manage to both file the tax return and pay the assessed tax by this date. We therefore bring you practical information on this legal obligation, as well as on the electronic filing of a tax return. Find out who is obliged to file the return electronically, what you need for it, and where to obtain an electronic signature with the legal force enabling the signing of an electronic tax return.

Who Must File a Tax Return Electronically?

The taxation of the income of natural and legal persons is governed by Act No. 595/2003 Coll. on income tax (hereinafter the “Income Tax Act”). Under this legal regulation, the obligation to file an income tax return applies to a wide range of natural and legal persons, including employees and entrepreneurs.

Tax Returns of Natural Persons

An income tax return for natural persons must be filed by every natural person whose taxable income exceeded the sum of EUR 2,876.90. Any income earned that is subject to tax under the Income Tax Act and is not exempt from tax is counted towards this sum.

Expert TIP:

However, even natural persons whose income did not reach the sum of EUR 2,876.90 can voluntarily file a tax return. The reason for such a decision is the fact that in some cases you can obtain a tax overpayment. If you are not sure whether this applies to you, we recommend consulting this option with your accountant.

Tax Returns of Legal Persons

An income tax return for legal persons must be filed by every legal person except for the following exceptions:

• legal persons that are not established for business and have only income that is not subject to tax or is taxed by withholding,
• civic associations, if they have only income that is not subject to tax or is taxed by withholding, and income from membership fees that is exempt from tax,
• budgetary and subsidized organizations, if, in addition to income taxed by withholding, they have only income exempt from tax,
• other entities (registered churches, religious societies, the National Bank of Slovakia and others).

Postponing the Tax Return

The law allows obliged persons to postpone the filing of an income tax return. The notice of the extension of the deadline for filing the tax return is submitted on a prescribed form for both natural and legal persons. In this form, it is also not necessary to state the reason for the postponement, and the tax administrator does not have to approve this reason. The request to postpone the tax return must likewise be submitted by 31 March 2026 at the latest.

The Deadline for Electronic Filing of a Tax Return

A tax return filed electronically must also be filed by 31 March 2026 (or within the extended deadline, if you submit a request to postpone the tax return). If this day falls on a Saturday, Sunday or another public holiday, the last day of the deadline is the next working day. Persons who are obliged to file a tax return electronically cannot do so by any other means (in person, by post).

Under Act No. 563/2009 Coll. on tax administration (the Tax Code) and on amendments to certain acts, the following persons have an obligation to file a tax return:

• a tax entity that is a payer of value added tax,
• a legal person registered in the Commercial Register of the Slovak Republic,
• a natural person – entrepreneur who is registered for income tax (since 1 July 2018),
• a tax adviser on behalf of a tax entity they represent in tax administration,
• a representative not listed in the preceding points who represents a tax entity obliged to deliver by electronic means (for example, an accountant).

Other persons can choose the form of filing a tax return according to their own preferences.

Registration for the Electronic Filing of a Tax Return

If you want to file a tax return online, or you are among the persons who must do so by law, the first step is registration on the portal of the Financial Administration of the Slovak Republic. If you have already registered in the past, you do not need to register again.

You will find the procedure for registration and authorization on the portal of the Financial Administration of the Slovak Republic via an eID card in this practical video guide.

In practice, there are two ways to register with the Financial Administration to file a tax return:

• registration via the slovensko.sk web portal,
• registration by filling in a registration form on the website of the Financial Administration.

Important notice:

The registration process must be completed in person with the tax administrator at the locally competent tax office, where the applicant personally signs the agreement on electronic delivery (for natural persons) and requests authorization (for legal persons).

If you are filing a tax return online for the first time, it is important to begin the entire registration and authorization process well in advance, because it can take several days.

Electronic Filing of a Tax Return and the Electronic Signature

To file a tax return electronically you need:

• Registration and authorization: To file a tax return online (electronically), you must register on the portal of the Financial Administration of the Slovak Republic.
• Logging in: You must then log in to your account using an eID card (an electronic identity card).
• Filling in the form: In the next step, you choose the relevant income tax return form and fill it in properly.
• Electronically signing the form: You must sign this form with a qualified electronic signature.
• Electronically submitting the form: When signing the properly completed form with a qualified electronic signature, you click on “Sign and Submit”.

Before filing the tax return, you must have a signing application installed.

How to Obtain a Qualified Electronic Signature (QES)?

It follows from the information above that, to file a tax return online, you need to go through the registration process, ensure the relevant software is installed, and obtain a qualified electronic signature.

You can obtain a QES quickly and easily via the NFQES online platform. This comprehensive platform helps individuals and companies optimize and secure electronic communication, in compliance with the strictest security rules and quality standards within the European Union as well as Slovak legislation.

The operator of the NFQES online platform is the company BRAIN:IT, which is a certification authority under the eIDAS rules for all levels of electronic signatures. On it you will obtain a qualified electronic signature and all the important and practical information about electronic signing.

A QES fully replaces a handwritten signature and you can also use it in contact with other commercial entities or public bodies, organizations and institutions. With electronic signing using a signature with legal force, you can also save on fees for various services. Find out where you can save with an electronic signature.

File Your Tax Return Faster

Filing a tax return online is already mandatory for many persons, and for everyone else it represents the fastest way to fulfil a legal obligation without visiting an office. The key to a successful electronic filing is timely registration on the portal of the Financial Administration, a functioning authorization and a QES.

If you set up the entire process well in advance, the filing of the tax return online itself will take only a few minutes. Thanks to a correctly set up electronic signature, you gain not only a fulfilled legal obligation but also a more efficient way of working with documents going forward.