In the course of running a business, entrepreneurs often deal with various types of accounting documents. One of the most common is the WZ document (goods issue note), which may appear when you do not receive a standard invoice. Can such a document be sufficient proof of purchase, and can it be included in business costs? This question raises many doubts among business owners keeping a KPiR (tax revenue and expense ledger).
Knowing the rules on source documents is essential for keeping your records correctly. Documenting business transactions incorrectly can cause problems during a tax audit and prevent expenses from being treated as tax-deductible costs. That is why it is worth looking closely at which documents the legislator accepts as the basis for entries in the KPiR. The same question comes up with costs of mandate contracts in the KPiR.
Documents that can be the basis for an entry in the KPiR
The legislator has set out in detail which documents can be the basis for entries in the tax revenue and expense ledger. From 1 January 2026, these rules are set out in the regulation of the Minister of Finance and Economy of 6 September 2025 on keeping the tax revenue and expense ledger (Journal of Laws (Dz.U.) 2025 item 1299), which replaced the earlier regulations of 2003 and 2019. The catalogue of accounting documents in it is strictly defined (§ 6–9) and is not open to free interpretation. When a WZ note itself fits into this catalogue is explained in our article on recording a WZ note in the KPiR.
The source documents that can be the basis for an entry in the KPiR are listed in § 6(3) point 1 of the regulation. They include invoices, VAT RR invoices, bills (rachunki) and customs documents. All these documents must be issued in accordance with separate legal provisions
The basic source documents that can undoubtedly be the basis for an entry in the KPiR are:
- Invoices issued in accordance with the VAT rules
- VAT RR invoices documenting purchases of agricultural products from a flat-rate farmer
- Bills for transactions not subject to the invoicing obligation
- Customs documents (e.g. a customs declaration on the import of goods)
Each of these documents must meet specific formal and substantive requirements to be accepted as a valid accounting document. Incomplete or incorrect documents may make it harder to treat expenses as tax-deductible costs.
The regulation also provides for documents recording a reduction of tax-deductible costs or an increase in revenue under Article 22p of the PIT Act (§ 6(3) point 2). They are prepared when a payment for a transaction worth more than PLN 15,000 with another business (Article 19 of the Entrepreneurs' Law) was made without using a payment account or – in 2026 – to an account that is not on the VAT taxpayer white list; from 1 January 2027 (Dz.U. 2026 item 1371), for invoices issued from that date, only a payment made without using a payment account counts
Additional documents confirming payments
In addition to the basic source documents, the legislator allows additional documents that can affect the amount of tax-deductible costs or revenue. These documents are particularly important when you need to document a payment or correct entries made earlier.
These documents must contain strictly defined elements to be accepted as valid accounting documents:
- The date the document was issued and the month in which tax-deductible costs are reduced or revenue is increased
- A reference to the invoice on which the transaction is based or, if there was no obligation to issue an invoice, a reference to the contract or other document that was the basis for treating the cost as tax-deductible
- The amount by which the taxpayer reduces tax-deductible costs or increases revenue
- The signature of the person preparing the document
Documents under Article 22p of the PIT Act are particularly important for transactions above PLN 15,000 paid in cash or to an account not on the white list. They must contain all the required elements to be the basis for corrections in the records. If any of the required elements is missing, the document may be challenged
These additional documents complement the basic source documents and allow all aspects of business transactions to be documented correctly, especially those related to payments.
Other accounting documents accepted as the basis for an entry
Apart from the documents listed expressly as the basic proof of purchase, the regulation also provides for other categories of accounting documents that can be the basis for entries in the KPiR. These documents are auxiliary and organisational in nature, but they are just as important for keeping the records correctly.
The catalogue of other accounting documents includes:
- Accounting notes prepared to correct an entry relating to a business event arising from an external or internal document, received from the taxpayer's contractor or given to the contractor
- Proof of postal and bank charges
- Other proof of payment of charges, including those made on the basis of payment books
- Documents containing the data listed in § 6(3) point 3 of the regulation
- Internal documents – only in the cases listed in § 8 (e.g. per diems for business trips, court and notary fees, the part of rent and utility charges attributable to the business)
Accounting notes are particularly important when correcting bookkeeping errors. They can be issued by the taxpayer or received from contractors. Each accounting note must contain a clear justification for the correction and identify the document it relates to
These additional accounting documents make it possible to document all business transactions comprehensively, including corrections, certain internal expenses and various charges. Using them correctly is essential for keeping the records continuous and complete. We check and book our clients' accounting documents as part of our accounting services.
Formal requirements for accounting documents
For a document to be accepted as a valid accounting document and be the basis for an entry in the KPiR, it must meet certain formal requirements. These requirements are set out in detail in § 6(3) point 3 of the regulation and apply to other documents, listed in § 7 and § 8, that are neither invoices nor documents under Article 22p.
Each accounting document must contain the following elements:
- A reliable identification of the issuer or of the parties to the business transaction
- Full identification data, including the names and addresses of all parties to the transaction
- The date the document was issued and the date or period of the business transaction
- The subject of the business transaction and its value
- The quantity of the subject of the transaction, if it can be measured in natural units
Dates in accounting documents are crucial for recognising a transaction in the right settlement period. If the date of the business transaction is the same as the date the document was issued, one date is enough, but this must be made clear
In addition, the document should be:
- Signed by the persons authorised to document business transactions properly
- Numbered or marked in another way that allows it to be linked to the entries made on its basis
- Prepared in a legible and durable way
- Protected against unauthorised access and changes
These requirements are meant to ensure that the accounting documentation is reliable and complete and that the correctness of the records can be checked effectively.
What a WZ document is
The WZ document (Wydanie Zewnętrzne – external goods issue) is one of the most commonly used warehouse documents in businesses. Its main function is to document the issue of goods, materials or other assets from the company's warehouse to outside the organisation.
The WZ document is issued by the business releasing the goods – for that business it is its own warehouse document, and for the recipient it is an external document. It is used to record the following operations:
- Issue of goods to customers as part of a sale
- Transfer of auxiliary materials for external use
- Issue of assets to other entities (e.g. for repair or on loan)
- Transfer of assets to organisational units
- Other operations involving the issue of assets outside the business
A WZ document is usually issued when the goods physically leave the warehouse, which often happens before the sales invoice is issued. It serves as the basis for the sales or finance department to prepare the invoice, which documents the settlement side of the transaction
A typical WZ document contains the following information:
| Document element | Description | Significance |
|---|---|---|
| Issue date | When the document was prepared | Sets the chronology of the operation |
| Release date | When the goods physically left | Key for warehouse records |
| Document number | Unique WZ identifier | Allows linking with other documents |
| Type of goods | Detailed description of the item released | Identifies the subject of the operation |
| Issuer's details | Name, address, NIP (tax identification number) of the issuer | Identifies the releasing party |
| Recipient's details | Name, address, NIP of the recipient | Identifies the receiving party |
Legal analysis of the WZ document as an accounting document
The key question is whether a WZ document can be accepted as a valid accounting document entitling you to record the transaction in the KPiR. To answer it, you need to analyse the WZ document against the requirements of the regulation.
The WZ document is not expressly listed in the catalogue of accounting documents in § 6(3) and § 7 of the regulation. This means it is not one of the documents that can automatically be the basis for an entry in the KPiR without further analysis of its content. An exception is provided in § 9 of the regulation: if trading goods or basic or auxiliary materials (raw materials) were delivered before the invoice was received, the taxpayer prepares a detailed description of the delivery (the supplier's first name, surname or name and address, quantity and type, unit price and value) and makes the entry in the ledger on that basis. The person who received the delivery confirms the description with a date and signature. You do not need to prepare the description if the purchase is documented by a supplier's specification meeting these requirements – a WZ document with prices can play this role, but only until the invoice is received, and it must then be attached to the invoice.
A manufacturing company received only a WZ document without an invoice from its raw-material supplier. The document contained the supplier's details, the type and quantity of the raw material, unit prices and value, and the person who received the delivery confirmed it with a date and signature. The company could record the purchase in the KPiR on the basis of this document as a supplier's specification (§ 9(2) of the regulation). However, the document did not replace the invoice: once the invoice arrived, the company attached it to the WZ, entered any difference in value in the ledger on the day the invoice was received, and could deduct VAT only on the basis of the invoice.
Outside the situation in § 9, a WZ document would have to fall within the catalogue of accounting documents in § 6(3) and § 7 and meet the requirements in § 6(3) point 3 of the regulation for other accounting documents. Analysing these requirements for a typical WZ document reveals the following problems:
- A WZ document often does not contain all the required identification data of the parties to the transaction
- It may not specify precisely the nature of the business transaction from an accounting perspective
- It often lacks elements confirming the settlement side of the transaction
- It may not contain all the required signatures of authorised persons
The regulation does not list the WZ document among accounting documents (§ 6(3) and § 7), so a WZ on its own does not replace an invoice as a permanent basis for recognising costs in the KPiR. It can only – when buying trading goods or materials delivered before the invoice – act as a supplier's specification under § 9(2), if it contains all the data required for the delivery description
Legal and practical consequences
The fact that a WZ document cannot be accepted as a valid accounting document has far-reaching consequences for businesses. If no invoice is issued and the WZ does not meet the conditions of a supplier's specification under § 9, an expense documented only by a WZ document, as a rule, cannot be entered in the KPiR or treated as a tax-deductible cost, which directly affects the tax base. Without an invoice you also cannot deduct VAT – the right to deduct arises no earlier than in the period in which the invoice is received (Article 86(10b) point 1 of the VAT Act).
The practical consequences include:
- Not being able to treat the expense as a tax-deductible cost
- A higher income tax base
- The risk of additional tax liabilities in the event of an audit
- The need to keep additional off-book records
- Problems recovering receivables from contractors
Businesses that have received only a WZ document should promptly ask the supplier to issue a proper accounting document. This may be an invoice, a bill or another document meeting the requirements of the regulation. A seller who is a VAT payer must issue an invoice for a sale to another taxpayer (Article 106b(1) point 1 of the VAT Act). Delays in obtaining a proper document may cause problems with recognising the transaction in the right settlement period
Where it is impossible to obtain a proper document from the contractor, businesses may consider the following steps:
- Preparing a delivery description (§ 9 of the regulation), if the goods or materials arrived before the invoice
- Obtaining additional documents confirming the transaction
- Securing proof of payment and correspondence with the contractor
- Consulting a tax adviser about the situation
- Considering whether to pursue claims against the contractor
Alternative documentation solutions
Where the WZ document is the only document received, businesses can take steps to complete the documentation of the business transaction. It is essential to follow the rules set out in tax law and in the KPiR regulation.
Possible corrective steps include:
- Asking the contractor to issue an invoice or bill
- Preparing an internal document to make up for the gaps in the WZ document
- Obtaining written confirmation of the transaction details from the contractor
- Securing additional evidence confirming that the transaction took place
- Documenting correspondence with the contractor about completing the documentation
A delivery description under § 9 of the regulation (or a supplier's specification) allows you to record the purchase of trading goods or materials in the KPiR before the invoice is received, but it is temporary – it must be attached to the invoice when it arrives. Other internal documents, outside the cases in § 8, will not replace the required accounting document
If it is impossible to obtain a proper document from the contractor, businesses should:
- Document all steps taken to obtain a proper document
- Keep copies of correspondence with the contractor
- Prepare an explanatory note on the circumstances of the transaction
- Secure all evidence confirming that the business transaction actually took place
- Consult a tax or legal adviser about the situation
