You finished the work in June and discover in August that you never issued the invoice. Or an incoming document from last quarter surfaces while you tidy your email. Both are a "forgotten invoice", but the right response differs. What decides it is whether the document is one you issued or one you received, whether it already exists, whether it has been paid, and whether you are registered for DPH (Czech VAT).
The most important thing is not to cover the mistake up. Do not invent an older issue date, do not delete the surrounding documents, and do not move the DUZP — datum uskutečnění zdanitelného plnění, the date of taxable supply — just so the supply falls into the current month. First work out what actually happened, then fix the records and, where needed, the tax filings.
Start by telling four situations apart
| What happened | First step | Main risk |
|---|---|---|
| You did the work but never issued the invoice | Issue it now with the real details of the supply | For a VAT payer the tax may have belonged to an earlier period |
| You issued the invoice but never sent it to the customer | Send the document and keep evidence of the correspondence | Late payment and a weaker position if you have to enforce it |
| An incoming invoice arrived late | Put it into the records and assess which tax period it belongs to | A missing expense or a deduction claimed too late |
| You had the document but never recorded it | Compare it against the returns already filed | A VAT return, control statement or income tax return may need correcting |
You never issued the invoice at all
Issue it without further delay. Use the real current issue date and the next free number in your series. At the same time state the real date of supply, matching the contract, the handover of the work or whatever other moment is decisive. You cannot repair a late issue by creating a document that pretends to have come into existence two months ago.
For a VAT payer the law generally requires the tax document to be issued within 15 days of the day the duty to declare the tax arose or the supply took place. If you miss that deadline you still have to issue the invoice. But the date the document was created does not overwrite the original DUZP and does not move the duty to declare the tax.
If you are not registered for VAT there is no problem with paying VAT into an old period, but you still need the receivable and the income recorded correctly. If the customer has not paid yet, the invoice remains a receivable. If they paid before you issued it, assign the payment to the document and keep the evidence showing what it was for.
The invoice exists but the customer never got it
Here the tax document itself usually does not change. Check that the details are right and send it to the customer as soon as you can, with a short explanation. Do not change the issue date or the number just to "restart" the payment period. You can agree a new due date with the customer, but that agreement should be traceable.
If the invoice is already overdue, do not open with a threatening reminder. Admit the administrative slip, propose a reasonable new date, and confirm that both the content of the supply and the price match what you agreed. After a long delay, check the limitation period for the receivable and the contract terms as well.
What to do as a VAT payer
For VAT what counts is the real date of taxable supply, or the day payment was received if the duty to declare the tax arose earlier. A late-issued invoice can therefore belong to a period for which you have already filed the VAT return and the control statement (kontrolní hlášení).
Work through it in this order:
- establish the correct DUZP from the order, the contract, the handover protocol and the payments,
- issue the document with the current issue date and the real DUZP,
- check whether a VAT return has already been filed for the original period,
- check the effect on the control statement,
- if the last known tax goes up, file the appropriate additional return and follow-up control statement for your particular situation,
- keep the explanation and the supporting documents for the correction.
If you find the error before the ordinary filing deadline has passed, a corrective filing may be available. After the deadline you work with an additional return and, where relevant, a follow-up control statement. The exact route depends on what has already been filed and whether the tax liability changes. For a significant amount, or several periods, bring in an accountant or tax adviser.
How income tax works out
For a sole trader keeping tax records (daňová evidence), taxable income normally turns on the moment the money actually arrives. An invoice issued in December and paid in January therefore usually enters income in January. At the same time you record the unpaid invoice as a receivable at year end.
If you keep full accounts, different rules apply and revenue does not simply follow the date of payment. There can also be particular effects when you cease activity, change the way you claim expenses, or enter the flat-tax scheme (paušální daň). This article does not replace an individual assessment of those transitions.
A sole trader on flat-rate expenses must not forget that they, too, keep records of income and receivables. A missing issued invoice is not a problem only for those claiming real expenses.
An incoming invoice arrived late
First check that the document is factually right, relates to the business, and has not already been recorded under another number or from a bank movement. Then enter it with its real details — do not rewrite the supplier's issue date or the DUZP.
In tax records a real expense is usually reflected when it is paid, assuming it is deductible. A December invoice paid in January will therefore normally affect the following year. An unpaid document, on the other hand, may be a liability you need to record at the end of the period.
A VAT payer has to separate the date of supply from the moment the tax document is in hand. The deduction cannot be claimed before the statutory conditions, including holding the document, are met. You do not always have to squeeze it into the month shown as the DUZP; the deduction can generally also be claimed in a later period within the statutory time limit.
For entitlements arising from 1 January 2025 onwards, the general rule is that the deduction cannot be claimed after the end of the second calendar year immediately following the year in which the entitlement arose. There are special situations and exceptions, so do not judge a very old or a significant document by that one sentence alone.
The document is from last year
The turn of the year causes the most anxiety, but the method does not change: separate the invoice, the payment, the DUZP and the returns already filed. The year in the invoice number does not by itself decide the year of taxation.
- An issued, unpaid invoice of a non-VAT trader in tax records: you record the receivable; income normally arises on payment.
- A taxable supply issued by a VAT payer: VAT follows the real DUZP, or the earlier moment the duty arose, not the payment of the invoice.
- An expense received, in tax records: you assess the business link and the date of payment.
- A VAT deduction from a document received: you need the tax document and you watch the statutory time limit.
If an income tax return has already been filed and the newly discovered fact changes the last known tax, a duty to file an additional return may arise. For an expense that would only reduce the tax, the rules and the decision whether to file differ. Have the effect confirmed before you reopen a closed year.
What definitely not to do
- Do not enter an old issue date. The document should show when it really came into existence.
- Do not move the DUZP. It has to match the real supply.
- Do not reuse an old, taken number. Keep the series continuous and unambiguous.
- Do not delete the invoices that follow. One gap is no reason to break the history of the whole record.
- Do not enter a received document twice. Check the number, the supplier, the amount and the bank payment before you record it.
- Do not wait for the end of the year. With VAT, interest and other consequences can grow with the delay.
When to cancel and when to issue a corrective document
If the invoice captures a supply that really was delivered and only some detail is wrong, do not reach for cancellation automatically. A document you have sent should stay traceable, and the correction has to match the nature of the error. A corrective tax document may be needed when the price changes or the supply is cancelled. Cancellation suits a document that should never have existed and never properly entered circulation.
We explain the difference in detail in Credit notes and corrective tax documents. Inside the app, follow the help centre article on cancelling and deleting invoices so the record stays continuous.
How to stop invoices being forgotten
- Invoice from an event. Finishing the work, signing the handover protocol or the end of the month has to trigger a concrete task.
- Use one place for documents. Issued invoices, received expenses and attachments should not be split between a spreadsheet, your email and your phone.
- Review open jobs once a week. Ask: what has been delivered but not yet invoiced?
- Compare your records with the bank once a month. An unrecognised payment often reveals a missing document; an unpaid invoice needs a reminder.
- Close the period before you file VAT. Check the DUZP, the number series, the documents received and any unusual amounts.
Taxorio keeps invoices, expenses, attachments and payment status in one place. Numbering runs automatically and you can upload or photograph a document you receive. On the PRO plan you can also prepare the XML for the VAT return and the control statement. When you do discover something late, you at least have a complete history to correct it from safely.
Checklist when an old document turns up
- Is the document one you issued or one you received?
- Did it already exist, or are you creating it now?
- What is the real date of supply and the real date of payment?
- Are you and the other party registered for VAT?
- Has a VAT return, control statement or tax return already been filed for the period concerned?
- Does the document change the last known tax?
- Do you have the evidence that explains the correction?
One forgotten invoice is fixable. The worst option is a second mistake made while hiding the first. Record what happened as it happened, and for a closed tax period have the right type of filing confirmed.
Official sources
- General Financial Directorate: information on invoicing rules
- Financial Administration: changes to the time limit for claiming a VAT deduction from 2025
- Financial Administration: records of entrepreneurs and the self-employed
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.