How to Check an EU VAT Number: VIES Guide

1. What Is VIES and How Does It Work?

VIES stands for VAT Information Exchange System. It is the official online tool operated by the European Commission that allows businesses to verify whether a given EU VAT identification number is valid and currently active.

When you enter a VAT number into VIES, the system doesn't maintain its own database of VAT numbers. Instead, it sends a real-time query to the national tax authority of the member state that issued the number. The national database responds with a confirmation (valid or invalid), and VIES relays that answer back to you.

This is an important distinction: VIES is a relay system, not a database. It depends on the availability of 27 separate national databases. If the database for a particular country is down for maintenance, VIES cannot verify numbers from that country — even though the number itself may be perfectly valid.

VIES is free to use and available to anyone. You do not need to be VAT-registered yourself to check a number. The tool is accessible via the European Commission's website, and many third-party tools (including our free VAT number checker) use the same underlying system.

2. Why You Need to Verify VAT Numbers

Verifying your customer's VAT number isn't just good practice — it's a legal requirement if you want to apply the reverse charge mechanism on B2B cross-border sales within the EU.

Here's why this matters:

The reverse charge requirement

Under Articles 44 and 196 of the EU VAT Directive (Council Directive 2006/112/EC), when you sell services to a business in another EU member state, the reverse charge mechanism applies. This means you invoice at 0% VAT, and your customer self-accounts for the VAT on their own return.

But there's a condition: the reverse charge only applies if your customer has a valid VAT identification number. If their number is invalid — whether due to a typo, an expired registration, or fraud — the reverse charge does not apply, and you become liable for the VAT you should have charged.

Financial liability

If you apply the reverse charge without verifying the VAT number, and a subsequent audit reveals the number was invalid, your tax authority will hold you responsible for the uncollected VAT. You'll owe the full VAT amount (potentially 19-27% of the sale price), plus interest and possible penalties.

Consider the math: on a €10,000 invoice to a German customer (19% VAT), failure to verify could cost you €1,900 plus penalties. Multiply that across several invoices and the exposure becomes significant.

Invoice compliance

A valid reverse charge invoice must include both your VAT number and your customer's VAT number. If your customer's number turns out to be invalid, the entire invoice is non-compliant. Your customer cannot reclaim the VAT, and your records are incorrect. Learn more about proper invoice requirements in our cross-border invoice guide.

3. Step-by-Step: How to Use the VIES Checker

Verifying a VAT number is straightforward. Here's the process:

When a number comes back as valid, VIES typically returns the registered business name and address associated with the VAT number. Cross-check this against the details your customer has provided. If the name or address doesn't match, investigate before proceeding.

4. What to Do If a VAT Number Is Invalid

An "invalid" result from VIES doesn't always mean your customer is lying. There are several common reasons a valid business might have an invalid number:

• Typo in the number. A single wrong digit will cause a failure. Ask your customer to double-check and resend their VAT number. This is the most common cause of failed checks.
• Wrong country prefix. The customer may have provided the number without the country prefix, or with the wrong one. Ensure the prefix matches their country of registration.
• Registration in progress. New businesses may have applied for VAT registration but not yet received their number, or the number may not yet be active in the national database.
• Deregistered number. The business may have been deregistered — either voluntarily (they fell below the registration threshold) or involuntarily (non-compliance). Ask the customer to confirm their registration status with their local tax authority.
• Database delay. National databases are not always updated in real time. A newly issued number may take days or weeks to appear in VIES.

What you should do

1. Ask the customer to re-verify their number. Send them the exact number you checked and ask them to confirm it's correct.
2. Try again in 24-48 hours. If the number is new, it may not have propagated to VIES yet.
3. Ask for proof of registration. Request a copy of the customer's VAT registration certificate from their national tax authority.
4. If still invalid: charge VAT. If you cannot verify the number, you must treat the sale as B2C and charge VAT at the appropriate rate (either your home rate or the destination rate under OSS). You cannot apply the reverse charge without a valid, verified VAT number.

5. What to Do When VIES Is Down

VIES has a well-known reliability problem. The system depends on 27 national databases, and at any given time, one or more of those databases may be offline for maintenance. This typically manifests as an "unavailable" or "member state unavailable" response rather than an outright "invalid."

Here's how to handle it:

Short-term outages (hours)

If VIES returns an "unavailable" response for a specific country, try again in a few hours. Most maintenance windows are short — a few hours at most. The European Commission publishes a VIES availability schedule showing planned maintenance windows for each member state's database.

Persistent outages (days)

If a country's database is down for an extended period, you have several options:

• Use an alternative verification method. Some member states have their own national VAT verification tools that may work when VIES is down. For example, Germany's BZSt offers a separate confirmation service.
• Document your attempts. Take screenshots showing the "unavailable" response with the date and time. This evidence shows you attempted to verify in good faith.
• Proceed with reasonable evidence. If you have the customer's VAT number, their business name and address match the expected format, and you can show you attempted VIES verification, most tax authorities will accept that you acted in good faith. However, do follow up and verify once the system is back online.
• Use our VAT checker tool, which will clearly indicate when a member state database is unavailable vs. when a number is genuinely invalid.

6. VAT Number Formats by Country

Every EU member state has its own VAT number format. Knowing the expected format helps you catch obvious errors before submitting to VIES. Here are all 27 EU member states:

Note that some countries use letters within the number (France, Ireland, Cyprus, Spain), while others are purely numeric. The country prefix is always two letters. When entering a number into VIES, include the prefix.

7. When to Check: Before Every B2B Invoice

The most common question is: "How often do I need to verify a customer's VAT number?" The answer is clear: before every invoice, or at minimum, before each billing cycle.

Here's why periodic re-verification matters:

• VAT registrations can be revoked. A number that was valid when you onboarded a customer may have been deregistered since then. Tax authorities revoke VAT numbers for non-compliance, cessation of business, or falling below registration thresholds.
• Companies change structures. Mergers, acquisitions, or restructurings can result in new VAT numbers. The entity you originally contracted with may no longer exist under the same registration.
• Audit protection requires recent verification. If audited, you'll need to show that you verified the number around the time of each transaction — not just once, years ago.

Best practices for verification timing

• Monthly subscriptions: Verify at least quarterly. Set a reminder to re-check all active B2B customers' VAT numbers every 3 months.
• One-off invoices: Verify before each invoice.
• Annual contracts: Verify at contract signing and at each renewal.
• New customers: Always verify before the first invoice.

Automate this where possible. If you use accounting software or a billing system, many offer built-in VIES verification or integrations. Our VAT checker can be used for quick manual checks.

8. Record-Keeping Requirements

Verifying VAT numbers is only half the job. You also need to keep records of your verifications. If audited, you'll need to prove that you checked the number and what the result was.

What to record for each verification

• The VAT number checked
• The date and time of the check
• The result (valid, invalid, or unavailable)
• The name and address returned by VIES (if valid)
• The method used (VIES website, third-party tool, API)

How long to keep records

Record retention requirements vary by country, but the general rule across the EU is to keep VAT-related records for at least 7-10 years. Germany requires 10 years. Most other member states require 6-7 years. The safest approach is to keep all verification records for 10 years.

Format of records

Records can be kept digitally. Screenshots, exported CSV files from batch checks, or entries in your accounting system are all acceptable. The key requirements are that the records are complete, chronological, and unalterable (i.e., stored in a format that shows they haven't been modified after the fact).

9. Special Cases: Northern Ireland and Non-EU Countries

Since Brexit, the United Kingdom is no longer part of the EU VAT system. However, Northern Ireland retains its position within the EU VAT area for goods under the Windsor Framework. Northern Irish businesses engaged in trade in goods use VAT numbers with the prefix XI, which can be verified through VIES.

For services, Northern Ireland businesses are treated as UK businesses and use standard UK VAT numbers (with the GB prefix), which cannot be verified through VIES.

For businesses in non-EU countries (UK, Norway, Switzerland, etc.), VIES does not apply. You'll need to use the relevant national verification tool:

• UK: HMRC's "Check a UK VAT number" service
• Norway: The Brønnøysund Register Centre
• Switzerland: The UID Register

For sales to non-EU businesses, the reverse charge mechanism doesn't apply. Instead, the sale is typically outside the scope of EU VAT entirely. See our invoice guide for the correct wording for export invoices.

10. Automating VAT Verification

If you process more than a handful of B2B invoices per month, manual VIES checks become tedious. Here are your options for automation:

VIES SOAP/REST API

The European Commission provides a free SOAP web service for programmatic VIES queries. This allows you to integrate VAT verification directly into your billing or invoicing system. The API returns the same data as the web interface: validity status, registered name, and address.

Third-party APIs

Several services wrap the VIES API with additional features: batch checking, caching (to handle VIES downtime), historical verification logs, and webhook notifications when a number's status changes. These are worth considering if VAT verification is a critical part of your workflow.

Accounting software integrations

Many modern accounting platforms (Xero, QuickBooks, FreeAgent) offer built-in or plugin-based VIES verification. When you add a new contact with an EU VAT number, the software checks it automatically and flags any issues.

Manual checks with PayTaxFast

For quick manual checks, our free VAT checker provides instant results with a clean interface. It's ideal for freelancers, small agencies, and SaaS founders who handle a moderate number of B2B transactions.

11. Common Errors and Troubleshooting

Here are the most frequent issues people encounter when checking VAT numbers, and how to resolve them:

Error: "Invalid VAT number"

• Double-check the number for typos (most common cause)
• Ensure the country prefix is correct
• Verify the format matches the expected pattern for that country
• Ask the customer to confirm their number directly from their VAT registration certificate

Error: "Member State service unavailable"

• The national database for that country is temporarily down
• Try again in a few hours
• Check the VIES availability schedule for planned maintenance
• Document your attempt and follow up later

Error: "Request timeout"

• The VIES system is experiencing high traffic
• Try again in a few minutes
• If persistent, try our VAT checker as an alternative interface

Name/address mismatch

• The name returned by VIES doesn't match what your customer provided
• This could indicate a holding company structure, a recent name change, or a different legal entity
• Ask the customer to clarify — the VAT registration may be under a parent company or different legal name

12. Integrating VAT Verification Into Your Invoicing Workflow

The best approach is to make VAT verification a mandatory step in your invoicing process, not an optional one. Here's a recommended workflow:

1. Customer onboarding: Collect the VAT number as part of your customer signup or onboarding form. Verify it immediately using VIES or our VAT checker.
2. Before first invoice: Confirm the number is still valid. Cross-check the returned name/address against your records.
3. Invoice generation: Include both your VAT number and the customer's verified VAT number on the invoice. Add the required reverse charge statement: "Reverse charge — VAT to be accounted for by the recipient under Article 196 of Council Directive 2006/112/EC."
4. Periodic re-verification: Set a quarterly reminder to re-check all active B2B customers' VAT numbers.
5. Record the check: Log the date, number, and result of every verification.

Need help generating compliant invoices? Our invoice generator handles the correct legal wording automatically based on your scenario, and our tax calculator determines the correct rate for any cross-border transaction.

This guide is for informational purposes only and does not constitute tax or legal advice. VAT rules and VIES functionality may change. Always consult a qualified tax professional for advice specific to your situation.