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P&T Europe Services

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Czech company ID check & ARES lookup

Verify a business partner in seconds. The tool checks the IČO check digit, loads the name, address, VAT ID and insolvency from ARES, and adds the reliable/unreliable VAT payer status and published bank accounts from the Financial Administration register.

Input

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Eight digits. Leading zeros may be omitted.

The check digit is verified in your browser. Only after you press “Look up in ARES” is the number sent to the public ARES registry (Czech Ministry of Finance) to retrieve the company details.

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Data source: ARES — Administrative Register of Economic Subjects, Czech Ministry of Finance.

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How the IČO check digit works

A Czech company ID (IČO) has eight digits and the last one is a check digit. The first seven digits are multiplied by the weights 8, 7, 6, 5, 4, 3, 2, the products are summed and the sum is divided by eleven. The check digit follows from the remainder:

  • • remainder 0 → check digit 1
  • • remainder 1 → check digit 0
  • • otherwise → check digit 11 − remainder

For IČO 03680843: 0×8 + 3×7 + 6×6 + 8×5 + 0×4 + 8×3 + 4×2 = 129. The remainder after dividing by eleven is 8, so the check digit is 11 − 8 = 3 — and the eighth digit is indeed 3. The number is valid.

What ARES returns

ARES (the Administrative Register of Economic Subjects) is run by the Czech Ministry of Finance and aggregates several public sources. The tool shows:

  • • business name and registered address as recorded in the register
  • • the VAT ID (DIČ), if one has been assigned
  • • the legal form (s.r.o., a.s., sole trader, association…) and date of establishment
  • • whether the subject is active or has been dissolved
  • • whether it appears in the VAT payer register and whether it is a reliable or unreliable payer
  • • the accounts published by the tax authority — where it is safe to pay
  • • whether it appears in the insolvency register (ISIR)

Unreliable payers and liability for VAT

The unreliable payer status was introduced by the VAT Act in 2013. The tax authority flags a payer who has seriously breached their tax obligations — with a hard consequence for the customer: you become liable for the VAT such a supplier fails to remit. The same liability arises if you pay to an account other than a published one.

For VAT payers the tool therefore shows, straight from the Financial Administration register, whether they are a reliable or unreliable payer, and lists the accounts published by the tax authority. Before settling a larger invoice, simply compare the account on it against that list.

Why verify a partner before doing business

Before issuing an invoice or signing a contract it pays to check three things: that the subject exists and is active, that the name and address match your contract, and that the partner is not in insolvency. With VAT payers there is an added twist — you can become liable for the tax if you pay to an account other than the published one, so for larger payments it is worth checking the account in the Financial Administration VAT register too.

Data protection

The check-digit validation runs in your browser only. Only after you press "Look up in ARES" is the company ID sent to the public ARES registry and, for VAT payers, to the Financial Administration register — that one is queried through our server, because it does not allow direct browser queries. Data in both registers is public by law and nothing is stored on our side.

Official sources

The tool displays data as provided by ARES. For legal purposes, the entry in the relevant public register is always decisive.

We handle accounting and invoicing

From verifying partners through invoicing to tax returns — we take care of the whole agenda.

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Frequently asked questions

How is a Czech company ID (IČO) validated? +

A company ID has eight digits and the last one is a check digit. The first seven digits are multiplied by the descending weights 8, 7, 6, 5, 4, 3, 2 and the sum is divided by eleven. The check digit follows from the remainder: 1 if the remainder is 0, 0 if the remainder is 1, otherwise 11 minus the remainder. If the eighth digit does not match, it is a typo.

Where does the company data come from? +

From ARES (the Administrative Register of Economic Subjects) operated by the Czech Ministry of Finance. ARES aggregates data from the public registers, the register of persons, the trade licensing register, the VAT payer register and the insolvency register. The data is read directly from its public interface.

What does "unreliable VAT payer" mean? +

The unreliable payer status was introduced by the VAT Act in 2013. The tax authority flags a payer who has seriously breached their tax obligations. The consequence for you as a customer is significant: if you accept a supply from an unreliable payer, you become liable for the VAT they fail to remit. The tool reads this status directly from the Financial Administration register.

Why are published bank accounts shown? +

The tax authority publishes the accounts a VAT payer has designated for their business activity. If you pay a VAT payer to an account other than a published one and the tax is not remitted, you may become liable for it. For larger payments it is therefore worth comparing the account on the invoice with the published list — the tool shows it alongside the reliability status.

Why does the insolvency register matter? +

If the subject appears in the insolvency register (ISIR), the tool highlights it separately. It is a quick signal that insolvency proceedings are or were under way — before closing a deal it is worth looking into the insolvency register for the details of the case.

Is the company ID sent anywhere? +

The check digit is verified entirely in your browser. Only when you press "Look up in ARES" is the number sent to the public ARES registry and, for VAT payers, to the Financial Administration register (via our server, because that register does not allow direct browser queries). Both registers are public and we store nothing.

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