From when must I issue e-invoices, and what deadline applies?
Short answer
The obligation to issue e-invoices starts on 1 January 2027 for supplies that meet the conditions of § 85o of the VAT Act. The year 2026 is a preparatory and voluntary period. The e-invoice format does not change the general statutory deadlines for issuing an invoice; the applicable deadline must still be determined under § 71 and the following provisions of the VAT Act for the particular supply, payment received or correction.
Preparation
Voluntary testing, poster selection and ERP setting.
Mandatory regime
Start of obligation for legally determined deliveries.
By invoicing rules
Form XML does not in itself alter the time limit.
Validation and status
The period shall be completed by the correct execution and dispatch according to the procedure.
Detailed explanation
The effective date of mandatory e-invoicing and the deadline for issuing a specific invoice are two different matters. From 1 January 2027, the format and delivery channel of invoices will change for specified supplies. However, this does not mean that a business is granted a new general deadline simply because the invoice is in XML format. Internal processes must ensure that the invoice is issued within the statutory deadline, undergoes validation, is sent via a delivery service, and that the delivery status is tracked.
As set out in the law and technical rules
Section 85o of the VAT Act introduces the obligation to issue e-invoices. Section 76a governs delivery. Invoicing deadlines must be assessed in accordance with Section 71 et seq. of the VAT Act and the specific rules applicable to the case in question.
Practical examples
- A VAT payer supplies a service after 1 January 2027 to another trader, and the supply complies with Section 85o. The VAT payer issues the invoice as an e-invoice within the statutory time limit.
- An invoice for a supply from December 2026 is assessed according to the date and rules of the specific case, not merely according to the date on which the software issued it.
- If validation fails on the last day of the deadline, the company has not yet securely completed the sending process.
Common misconceptions
- “From 2027, everyone must issue e-invoices.” No. The decisive factor is the scope of persons and supplies under Section 85o.
- “XML extends the deadline.” No. The deadlines are set out in the VAT Act.
- “It’s enough just to create the invoice; there’s no need to track delivery.” With e-invoices, the delivery status and any errors are also important.
Conclusion
From 1 January 2027, the required invoice format changes for the specified supplies, but the statutory invoicing deadlines remain governed by the VAT Act.
Legal and technical basis
- Act No. 222/2004 Coll. on VAT, Section 71 et seq.
- Act No. 222/2004 Coll. on VAT, Section 76a
- Act No. 222/2004 Coll. on VAT, Section 85o
- Act No. 385/2025 Coll.
Related questions
This does not constitute legal advice. Sources: Act No. 222/2004 Coll. on VAT, Act No. 385/2025 Coll., Act No. 431/2002 Coll. on Accounting, official methodological and information materials from the Slovak Financial Administration on e-invoicing, EN 16931, Peppol BIS Billing 3.0 and OpenPeppol eDelivery documentation. Verified on 13 July 2026.
Official cases from the Slovak Financial Administration’s FAQs
The following questions and answers are taken from the current July FAQ from the Financial Administration and have been assigned to this topic. Grouping the cases prevents the creation of duplicate pages, whilst retaining the full answer and the exact wording of the question.
Example No. 13: What is the deadline for issuing an electronic invoice?
The deadline for issuing an invoice remains the same, i.e. 15 days. The legal obligation to issue and send an electronic invoice via a delivery service is deemed to have been fulfilled if the supplier has issued and sent the electronic invoice within 15 days of the delivery of the goods or the provision of the service. This means that once you have supplied the goods or provided the service, you have 15 calendar days to issue an invoice in electronic format in accordance with the specified standard. This also applies to corrective invoices issued to amend the tax base. If a customer subsequently informs you that you were obliged to issue an electronic invoice to them, the deadline for issuing the invoice is 15 days from the date on which they notified you of this. If the customer is unable to receive an electronic invoice via a delivery service and the supplier sends the electronic invoice via a delivery service, the supplier’s legal obligation to issue and send the electronic invoice via a delivery service is deemed to have been fulfilled.
Primary source: Financial Administration of the Slovak Republic, FAQ 9/VAT/2025/IM k e-invoice, July 2026 update. Processed and checked on 13 July 2026.
Review of questions from an earlier presentation
The presentation by the Slovak Accountants’ Centre was used solely to identify practical issues. The following conclusion has been updated in line with a subsequent FAQ from the Financial Administration and the applicable legislation; we do not treat the author’s suggestions, recommendations or incorrectly merged fragments as legal rules.
- slide/page 16: Will there be any changes to the deadline for issuing invoices?
Current conclusion: According to the FAQs, the standard deadline remains 15 days. If the customer subsequently notifies the supplier that an e-invoice should have been issued, the deadline is 15 days from the date of notification. Specific deadlines are always assessed on a case-by-case basis.
Primary sources: FAQ Financial Administration of the Slovak Republic k e-invoice, July 2026; Act No. 222/2004 Coll. on VAT Effective from 1. 1. 2027. Revised 13 July 2026.