Tax Number
vs VAT ID in

Slovenia

VAT IT
November 27, 2025

Understanding the Difference Between Tax Numbers and VAT IDs in Slovenia

For businesses operating in Slovenia, or those working with Slovenian entities, understanding the difference between a tax number and a VAT identification number (VAT ID) is more than a matter of semantics. It’s a fundamental distinction that can have real implications for compliance, invoicing, and cross-border transactions.

It’s easy to assume that a tax number and VAT ID are interchangeable. After all, they often contain the same digits. But in Slovenia, these identifiers serve different purposes, and using the incorrect one in the wrong context can lead to rejected invoices, delayed VAT refunds, or compliance complications.

Let’s break it down.

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What Is a Tax Number in Slovenia?

Slovenia’s tax number, also known as the Davčna številka, is a universal identifier issued by the Financial Administration of the Republic of Slovenia (FURS) to all taxable entities, including individuals, local businesses, and foreign entities with obligations in Slovenia.

This number is used for general tax purposes across a variety of direct and indirect tax-related processes. It serves as the foundation for the taxpayer’s identity in the eyes of the Slovenian tax authority.

A few key things to note:

All legal entities doing business in Slovenia are issued a tax number, even if they are not VAT registered.
This number is required when registering a business, filing income tax returns, or dealing with customs procedures.
The number consists of eight digits and is unique to each entity.

Think of the tax number as your national ID, it proves you exist in the Slovenian tax system, this number is your starting point.

What Is a VAT Identification Number?

The VAT identification number, also known as the Identifikacijska številka za DDV is specifically designated for VAT purposes. It is only issued to entities that are formally registered for VAT in Slovenia. Here is how it works: The VAT ID is simply the tax number preceded by the country prefix “SI.” So, if your tax number is 12345678, your VAT number becomes SI12345678 upon VAT registration.

This number is only issued to businesses that are VAT registered, meaning they have crossed the VAT registration threshold or have voluntarily opted to register for VAT.

The VAT ID is used to:

Charge and collect VAT on taxable supplies.
Submit VAT returns to the tax authority.
Reclaim input VAT on purchases and imports.
Engage in intra-community (cross-border EU) transactions, where both supplier and buyer need to be VAT registered.

It’s also necessary for validation checks through systems like the VIES VAT number validation system, which is commonly used for verifying the VAT status of EU-based suppliers and customers.

While the VAT ID shares digits with the tax number, it is only valid for VAT purposes once issued by FURS following registration. A tax number alone is not evidence of VAT registration.

Why This Distinction Matters

At first glance, the only real difference might seem to be the “SI” prefix, but overlooking the functional difference between the two can cause real problems:

1. Compliance and Reporting Accuracy

Using a tax number where a VAT ID is required can render your invoice non-compliant, particularly in cross-border B2B transactions. This can lead to:

Rejected invoices.
Delayed payment cycles.
Compromised eligibility for VAT reclaims.

For example: You are a company based in France invoicing a Slovenian partner. If they’ve only provided their tax number (without “SI”), they may not be VAT registered, meaning the transaction should be treated as domestic or consumer-level rather than intra-community B2B. The correct treatment of VAT hinges on knowing which number you are dealing with.

2. Foreign VAT Reclaim Opportunities

For non-Slovenian companies looking to reclaim Slovenian VAT under the EU 8th Directive or 13th Directive processes, having the correct VAT ID of your supplier is crucial. If you use the standard tax number instead of the VAT number, your claim might be flagged or outright rejected due to invalid invoice data. Your reclaim documentation must include the VAT ID with the correct “SI” prefix to be accepted.

3. Digital Compliance and E-invoicing

As Slovenia continues modernising its tax system with digital mandates and electronic invoicing protocols, distinguishing between general tax identifiers and VAT-specific numbers becomes even more important.

Systems designed to streamline B2B transactions rely on correct data input. Having the wrong ID associated with your business or your partners can cause automated processes to fail.

How to Check a Slovenian VAT Number

If you are unsure whether a Slovenian business is VAT registered, use the VIES VAT number validation provided by the European Commission.

Enter the “SI” prefix and eight-digit number to confirm:

Whether the number is a valid VAT ID
Whether the registration is active.

It’s a quick but vital step in ensuring your invoicing and tax treatment are correct, particularly for intra-EU transactions that rely on the reverse charge mechanism.

When Do You Need to Register for VAT in Slovenia?

Now that we’ve explored the differences between the two identifiers, the next logical question is, when does a business need to obtain a VAT ID in Slovenia?

You must register for VAT in Slovenia if:

Your annual taxable turnover exceeds €50,000.
You perform intra-community acquisitions or supplies.
You provide digital services, distance selling, or import goods into Slovenia.
You are a non-resident company with a taxable presence in Slovenia.

Voluntary VAT registration is also available if your business doesn’t meet the threshold and is looking to reclaim input VAT or enhance credibility with clients.

It’s true that the VAT ID in Slovenia is derived from the tax number. But don’t let that simplicity fool you into treating them as the same thing.

Here’s a quick analogy:

Think of your tax number as your national ID, everyone gets one, whether or not they travel. But your VAT ID is your passport, it’s what allows you to conduct business across borders, claim VAT, and appear in EU registries.

Using the incorrect number in the wrong context is like showing up at the airport with your driver’s license and expecting to fly internationally. You may get some confused looks, or worse, you may get turned away.

Get Clarity on Your Slovenian VAT Position

Managing VAT compliance in Slovenia (and across the EU) doesn’t have to be complicated, but it does require accuracy.

Whether you are unsure which number to use, when to register, or how to reclaim Slovenian VAT, VAT IT Reclaim is here to help. We offer full end-to-end VAT solutions for local and cross-border compliance, from registration to recovery.

Get in touch with our VAT specialists today to ensure your documentation is airtight and your reclaim potential is maximised.