The Standard Audit File (Jednolity Plik Kontrolny, or JPK) is an electronic format for reporting tax data to Polish tax authorities. For several years now, every active VAT taxpayer in Poland has been required to submit JPK_V7M (monthly) or JPK_V7K (quarterly) files. Despite the system being in place for some time, tax offices continue to identify numerous errors in submitted files. Below we discuss the most common problems and explain how to avoid them.

Structure of JPK_V7M and JPK_V7K

The JPK_V7 file consists of two parts:

  • Declaration part -- equivalent to the traditional VAT-7 declaration. It contains a summary of input and output VAT amounts for the given period.
  • Record part -- detailed VAT purchase and sales records. It contains data from individual invoices, including GTU codes, transaction type markings, and special procedure designations.

Both parts must be consistent and matching. Discrepancies between them are one of the most common reasons for inquiries from the tax office.

8 most common JPK errors

1. Incorrect GTU codes

GTU codes (from GTU_01 to GTU_13) are used to mark specific groups of goods and services. The most common errors include:

  • Missing GTU marking where required (e.g., GTU_12 for intangible services),
  • Assigning the wrong GTU code to a transaction,
  • Marking an invoice with a GTU code when it is not required.

Tip: Regularly update GTU code tables in your accounting system and verify them for each new category of goods or services.

2. Incorrect transaction type markings

JPK_V7 requires certain transactions to be marked with special codes, such as:

  • TP -- transactions with related parties,
  • SW -- mail-order sales from within the country,
  • EE -- provision of telecommunications and electronic services,
  • MPP -- mandatory split payment mechanism.

Omitting a required marking or applying it incorrectly is a frequent reason for corrections.

3. Missing or incorrect NIP numbers

The counterparty's NIP (tax identification number) must be correct and consistent with the data on the invoice. Common errors include:

  • Missing NIP on a domestic sales invoice (mandatory for B2B transactions),
  • Typos in the NIP number,
  • Entering the NIP with a country prefix (e.g., PL) in domestic transactions where it is not required.

4. Duplicate invoices

The same document recorded twice in the register is an error that is easy to overlook, especially when:

  • An invoice was booked manually and simultaneously imported from a system,
  • A correcting invoice was entered as a new document without linking it to the original,
  • Invoice duplicates were treated as new documents.

Tip: Before generating the JPK file, run a duplicate check report on your VAT register.

5. Incorrect VAT rates

Applying the wrong VAT rate happens more often than you might think. Typical situations include:

  • Applying 23% instead of 8% for construction services related to residential buildings,
  • Incorrectly applying the 0% rate (e.g., lacking documentation confirming export),
  • Confusing the exempt rate (zw) with the 0% rate.

6. Mismatched amounts between declaration and record parts

Totals in the record part must match the values in the declaration part. Discrepancies may result from:

  • Manual adjustments to the declaration part without updating the records,
  • Rounding errors,
  • Omitting certain documents from the records.

The tax office automatically compares both parts -- any discrepancy generates a request for explanation.

7. Late submission

The deadline for submitting JPK_V7M is the 25th day of the month following the reporting month. Late submission can result in:

  • An administrative fine of up to PLN 2,800,
  • Late payment interest on any outstanding tax liability,
  • Initiation of fiscal criminal proceedings in case of repeated delays.

8. Wrong reporting period or dates

Recording an invoice in the wrong reporting period is a common error, especially for invoices issued near the end of the month. The VAT obligation generally arises at the moment of delivery of goods or performance of services -- not at the time of issuing the invoice.

Consequences of JPK errors

Errors in JPK files do not go unnoticed. The tax office may:

  • Send a request to file a correction -- you have 14 days to respond,
  • Impose an administrative fine of up to PLN 2,800 per error,
  • Initiate verification activities or a full tax audit,
  • In extreme cases -- impose VAT sanctions of 15%, 20%, or even 100% of the understated liability.

How to prevent errors

Several proven practices that minimize the risk of JPK errors:

  1. Verify data before sending -- use the validation function in your accounting software.
  2. Use reliable software -- ensure your system generates JPK files compliant with the current logical structure.
  3. Conduct monthly reconciliations -- compare VAT records with sales and purchase registers.
  4. Train your staff -- ensure that personnel responsible for invoicing understand the rules for applying GTU codes and transaction markings.
  5. Archive documentation -- keep all invoices and documents confirming the applied rates and markings.

What to do when you find an error

If you notice an error after submitting JPK_V7, you should file a correction as soon as possible. The procedure is as follows:

  1. Prepare a corrected JPK_V7 file for the relevant period,
  2. Mark the file as a correction (not as an initial submission),
  3. Send the correction through the e-Deklaracje system or your accounting software,
  4. If the correction results in an increased tax liability -- pay the difference along with interest.

A correction filed before receiving a request from the tax office is treated more leniently -- administrative fines do not apply.

LinTax -- error-free JPK with double verification

At LinTax in Wroclaw, every JPK file undergoes double verification -- first an automated system validation, then a manual review by an experienced accountant. This ensures our clients can be confident their JPK is correct and complete. If you are looking for an accounting firm that pays attention to every detail, get in touch with us.