DUZP (datum uskutečnění zdanitelného plnění) is the date on which a taxable supply takes place. For the supplier it usually decides the period in which the VAT is declared, and it is not automatically the same as the date the invoice was issued. For the customer the DUZP alone is not enough: an input deduction can be claimed at the earliest for the period in which the payer holds the tax document. An advance received, meanwhile, is not "the DUZP of the advance" — but it can separately trigger an obligation to declare tax on the payment received.
What DUZP actually is
DUZP is the day on which the service was provided, the goods were delivered, or the subject of the taxable supply was otherwise fulfilled. It is the moment from which the tax obligations of both sides of the deal follow.
DUZP is not the same thing as the date of issue. For a supply of goods it is typically the day of delivery; for a service, Section 21 of the VAT Act may point either to the day the service was provided or to an earlier issue of the tax document. So treat the deadline for issuing the document and the moment the duty to declare tax arises as two separate questions.
Example: A developer finishes a web application and hands it over to the client on 28 January 2026. The invoice goes out on 3 February 2026. The DUZP is 28 January — the VAT on this transaction falls into the January 2026 tax period even though the invoice was issued in February.
Why DUZP matters so much
DUZP does several essential jobs in the VAT system:
1. It sets the tax period
VAT is declared for the period in which the DUZP fell, not the period in which the invoice was issued. For a monthly VAT payer that means an invoice with a DUZP of 31 January belongs in the January return even if it was issued on 10 February.
2. It drives the control statement
The control statement (form DPHKH1) is tightly bound to the VAT return. A transaction is reported in the control statement for the period matching its DUZP. A mismatch between the DUZP on the supplier's invoice and the DUZP the customer reports is one of the most common reasons the tax office sends out a notice.
3. It starts the clock for issuing the document
A VAT payer has to issue the tax document within 15 days of the DUZP. If the service was provided on 15 January, the tax document must be issued by 30 January at the latest.
4. It frames the right to deduct
A customer who is a VAT payer has to meet the conditions for the deduction and hold the tax document. If the document only reaches them in the period after the DUZP, then under the Financial Administration's current position they can claim the deduction at the earliest in that later period.
Setting the DUZP under Section 21 of the VAT Act
Section 21 of the VAT Act lays down the rules for different situations. Here they are in outline:
| Type of supply | When the DUZP arises |
|---|---|
| Supply of goods | the day of delivery under Section 13 of the VAT Act |
| Provision of a service | the day it is provided, or an earlier issue of the tax document, with the exceptions in Section 21 |
| Partial supply | as a rule the day stated in the contract; a contract for work has its own handover rule |
| Payment received before the supply | not a DUZP; where the future supply is sufficiently certain, a duty to declare tax on the payment arises |
Now the individual cases in more detail:
Supply of goods
For goods the DUZP is the day of delivery — the day the buyer acquires the right to deal with the goods as owner. An earlier payment does not move that date; if the future supply is known with sufficient certainty, a separate duty to declare tax on the payment received arises under Section 20a of the VAT Act.
Provision of a service
For services the DUZP is as a rule the day the service is provided, or the day the tax document was issued if that came earlier, unless one of the exceptions listed in the Act applies. A payment received before the service is again assessed separately under Section 20a.
Partial supplies (monthly retainers, ongoing services)
The VAT Act no longer has a special rule for "repeated supplies", so regularly invoiced services are handled as partial supplies under Section 21(7). A partial supply is one that, under the contract, is carried out in an agreed scope and at agreed intervals, and it is treated as made on the day stated in the contract. For a contract for work the handover rule applies to the work or a part of it as well, and whichever day comes first decides.
So for a monthly retainer, do not simply assume the last day of the tax period — check how the partial periods and the handover are actually agreed. Two special rules are worth remembering: a supply carried out over more than 12 months is treated as made on the last day of each calendar year (Section 21(8)); and an exempt lease of immovable property is treated as made no later than the last day of each calendar year (Section 21(10)).
Advances received (payment before the supply)
If the customer pays before the delivery is complete, no new DUZP arises. But on the day the payment is received the supplier has to declare tax on the amount received, provided the future supply is known with sufficient certainty — the goods or the service, the tax rate and the place of supply are all known. A tax document is then issued for the payment received.
Worked examples
A few situations typical for a sole trader:
Example 1: a one-off project
A graphic designer finishes a logo for a client on 15 January 2026 and issues the invoice on 20 January 2026 with 14 days to pay.
- DUZP: 15 January 2026 (the day the work was finished and handed over)
- Date of issue: 20 January 2026
- VAT period: January 2026
Example 2: a monthly retainer
A marketing consultant provides ongoing services for a monthly fee. The contract treats each calendar month as a separate partial supply ending on the last day of the month.
- DUZP: 31 January 2026 (the last day of the invoiced period)
- Date of issue: 1 February 2026 (it may be later, up to 15 February)
- VAT period: January 2026
Example 3: an advance before completion
A developer agrees a project with a client for 100 000 Kč plus VAT. The client pays an advance of 50 000 Kč on 10 January. The project is finished on 25 February.
- Payment received: 10 January 2026 — if the project, the rate and the place of supply are sufficiently certain, the developer declares VAT on the amount received and issues a tax document for the payment
- DUZP of the final invoice: 25 February 2026 (the day of completion) — the balance of 50 000 Kč plus 10 500 Kč VAT
- VAT on the payment received: January 2026
- VAT period for the balance: February 2026
Example 4: payment before goods are delivered
An e-shop owner takes an order and the payment on 28 January. The goods are dispatched and delivered on 2 February.
- Payment received: 28 January 2026 — where the supply is sufficiently certain, a duty to declare VAT on the payment arises
- DUZP of the supply of goods: 2 February 2026
- VAT period for the payment: January 2026
What goes wrong with a wrong DUZP
An incorrect DUZP on an invoice can have serious consequences:
- VAT in the wrong period — put a February DUZP where January belongs and you declare the VAT for the wrong period. The tax office can charge late-payment interest on the January VAT.
- A mismatch in the control statement — your customer reports the transaction for the period of the DUZP on the document they received. If your DUZP does not match reality, a mismatch appears, and the tax office evaluates those systematically.
- A notice from the tax office — a mismatch in the control statement brings a request for explanation. You have 17 days from delivery of the notice to your data box to respond (5 working days only if it is delivered another way); failing to respond risks a penalty of 30 000 Kč.
- A supplementary return — if you find the error yourself, you have to file a supplementary VAT return and, where relevant, a follow-up control statement. That means more administration and possibly interest.
DUZP on invoices you receive (expenses)
DUZP matters not only when you issue invoices but also when you record the ones you receive. As a VAT payer you can claim the deduction at the earliest for the period in which the statutory conditions are met and you actually hold the tax document. If the document only reaches you in the following period, the deduction cannot be pushed back into the period of the DUZP itself.
That is why it is worth recording the DUZP on every document you receive, and checking that date carefully when you enter the expense.
Practical tips
- Invoice as soon as possible after the work is done — the shorter the gap between the DUZP and the date of issue, the smaller the room for error.
- For ongoing services, start from the contract — if a calendar month is agreed as a partial supply ending on the last day of the month, the January supply has a DUZP of 31 January.
- Deal with advances straight away — receiving a payment is not a DUZP. But if the future supply is sufficiently certain, the duty to declare tax on the payment and to issue the corresponding tax document arises on the day it is received.
- Check the DUZP on invoices you receive — before you enter the expense, make sure the date on the document reflects what actually happened.
- Keep handover records — in a disputed case, a handover protocol is the evidence of the real delivery date, and therefore of the DUZP.
DUZP is one of those fields that looks like a formality until something goes wrong. Getting it right keeps you clear of tax office notices, penalties and avoidable administration. For a supply that has been carried out, the VAT follows the DUZP, not the invoice due date. An earlier receipt of a sufficiently certain payment is assessed separately under Section 20a of the VAT Act.
Official sources
- Section 21 of Act No. 235/2004 Coll., on VAT — carrying out a taxable supply
- Section 20a of the VAT Act — when the duty to declare tax arises and payments received
- Section 28 of the VAT Act — the duty to issue a tax document within 15 days
- Financial Administration: when an input VAT deduction may be claimed, from 2025
Taxorio scope: Taxorio provides invoicing and income/expense records for Czech sole traders. It is not full accounting or personalised tax advice. For an unsupported or unusual case, verify the treatment with a Czech accountant or tax adviser before filing.