How to issue an invoice line-items correction in KSeFGPT
Select the source invoice, change the required line, enter the reason, review the values before and after the correction, then submit the new document to KSeF.
- Module
- Invoices
- Reading time
- 5 min
- Difficulty
- Follow the instructions carefully and you will succeed
- Published
- August 21, 2026
- Author
- Rafał Zeidler
- Format
- Written guide and video
Written procedure
What you will do
You will prepare a correcting invoice for a document accepted by KSeF. You will select a line, change its data or values, review the state before and after the correction, and submit a new document.
The source invoice is neither edited nor deleted. KSeFGPT creates a separate correcting invoice that references the source invoice number, date and KSeF number.
Requirements
Before you start
Determine the correct reason and scope from your company records. This guide explains the interface and does not decide when a correction is required for tax purposes.
| Item | Description |
|---|---|
| Access | The company owner or an organization member with invoices:read and invoices:send. |
| KSeF connection | The selected company has an active token or certificate allowed to read and submit invoices. |
| Source invoice | An accepted invoice with a KSeF number. KSeFGPT does not allow a correcting invoice to be selected as the source of another correction. |
| Required data | New line values, correction reason, correction number, issue date and optional place of issue. |
| Starting point | After signing in, open Invoices → Issue. |
| Time required | About 3 minutes after the correct data has been established. |
Process recording
The recording shows source invoice selection, a line change, difference review and correction submission.
Select a line-items correction
In Issue, select Correction. On Pick correction type, select Change line items.
KSeFGPT opens Correction - change line items. Cancel full invoice is the zero-out path and has a separate guide.
Select the source invoice
Keep From KSeF list in Original invoice. Find the document by invoice number or date range and select the correct row.
Compare the invoice number, issue date, contractor and KSeF number first. A row without a KSeF number and a KOR invoice are disabled. Upload file is an alternative that accepts the source XML and requires the original invoice KSeF number.
Select and change a line item
After the lines load, select the checkbox next to the row you need to change. Select a value in the chosen cell and enter a new description, quantity, unit, price, amount or VAT rate.
When the net amount changes, KSeFGPT recalculates the related VAT and gross amounts. Check all three values. Only selected lines with an actual edit are included in the correction.
Complete the correction data
Enter a specific Correction reason. Check the proposed Correction number and replace it if your company numbering requires another value.
Confirm the Issue date and enter the Place of issue if it should appear in the document. Generate correction preview becomes available after a line is selected and changed and the reason, number and date are complete.
Check the source document in the preview
Select Generate correction preview. In the pink Correction block, check the corrected invoice number and date, its KSeF number and the reason you entered.
The number in the top right is the new correcting invoice number. It should not be the same as the source document number.
Check the differences and submit
Scroll to the line table. Compare the crossed-out value before the change with the new value and the delta shown below it. Check the net, VAT and gross summary.
Select the correct authorization method, select I take full responsibility for the correctness of data sent to KSeF and choose Submit to KSeF. Wait for the final screen instead of repeating the operation.
Final state
Check the result
Invoice accepted by KSeF confirms that the operation finished. Check code 200, the status description and the process reference number.
After refreshing Outcome, find the new document by its correction number. The source invoice remains in history and the correction is a separate document.
Diagnostics
If something does not work
Compare the symptom with the table below.
| Symptom | Likely cause | What to do |
|---|---|---|
| Correction is not available | Corrections are disabled for the account or current deployment. | Check invoice issue access and contact the KSeFGPT administrator. |
| The invoice row cannot be selected | The document has no KSeF number or is itself a KOR correcting invoice. | Select an accepted source invoice with a KSeF number. The current form does not support correcting a correction. |
| Failed to load line items | Reading the source from KSeF or parsing its XML failed. | Check the company, authorization method and invoices:read. Select the invoice again or upload a valid XML. |
| Generate correction preview is disabled | No line is selected, no value was changed, or the reason, number or date is missing. | Select at least one row, apply an actual change and complete the required fields. |
| Submission is unavailable | The company has no active KSeF connection or the member lacks invoices:send. | Configure a token or certificate and ask the owner for the required scope. |
| KSeF rejected the correction | The data, XML or sender permissions failed KSeF checks. | Read the error code and description. Correct the indicated issue before preparing another submission. |
What next
If all document values must be offset, follow How to cancel an invoice with a zero-out correction in KSeFGPT.
After acceptance, open the document in Outcome and download its XML, PDF visualisation and available UPO.
Issue a line-items correction in KSeFGPT
Sign in, select the source invoice and prepare a reviewed correcting document.
Related instructions
How to export KSeF invoices to a file in KSeFGPT
Choose the period and invoice direction, start a background job, check its status and download the finished spreadsheet.
How to cancel an invoice with a zero-out correction in KSeFGPT
Select the source invoice, prepare a separate document that reduces all its values to zero, review the preview and submit the correction to KSeF.
How to download an invoice as PDF, XML and UPO in KSeFGPT
Open an accepted outgoing invoice and download its source XML, a PDF visualisation in the selected language and the official UPO. UPO is available for a document submitted from KSeFGPT.
How to issue and submit a standard VAT invoice in KSeFGPT
Complete a standard VAT invoice, check the parties, line items and amounts, then submit the document to KSeF. The company needs an active KSeF connection and permission to submit invoices.