Rounding

How should rounding be handled in e-invoice?

⚠ Machine-translated answer, not yet manually reviewed. For the exact wording, see the Slovak original.

Short answer

Rounding must not silently conceal a difference between totals. Where rounding is used, it must be represented in the structured data and reconcile with the amount payable. First identify whether the difference arose in invoice lines, VAT, allowances or charges, or only in the final payment amount.

Rows

First the items

Check quantity, unit price, discounts and line amount.

VAT

Then TaxSubtotal

VAT blocks must fit according to rate and category.

The end

PayableRoundingAmount

Final rounding belongs in a separate field if you use it.

Test

ERP regression

Test rounding after every change in rates, prices or exports.

Detailed explanation

Many ERP systems can visually reconcile a difference of a few cents in a PDF, but XML validation checks the mathematical relationships. The line item total, total of line items, tax base, VAT, total amount and amount payable are subject to precise rules. Rounding at the end of the document must not mask an error in the line items or discounts.

As set out in the Act

For tax and accounting purposes, the rules for calculating the tax base and tax must be followed. The Peppol/UBL technical layer checks whether monetary amounts are consistent and whether any rounding is applied in the correct place.

Practical examples

  • Three items with a unit price in decimals will result in a difference of a few cents. The ERP system must have a clear rule specifying where rounding takes place.
  • The VAT rate is correct, but the TaxSubtotal is rounded differently to the items. The validation will flag this discrepancy.
  • The amount payable is manually adjusted in the PDF, but the XML lacks a PayableRoundingAmount. This is a problem.

Most common mistakes

  • “I’ll correct the cent difference in the final total.” First find out the cause; otherwise, you’ll just be covering up the error.
  • “Rounding is not covered by the validation.” It is precisely the summing rules that are among the most common validation errors.
  • “Different rounding in PDF and XML doesn’t matter.” It does matter. Both people and systems must see the same economic reality.

Conclusion

Rounding must be explainable, structured and tested, not used as a manual cosmetic adjustment.

Legal basis

  • Act No. 222/2004 Coll. about VAT, tax base and tax
  • Peppol BIS Billing 3.0: LegalMonetaryTotal and PayableRoundingAmount
  • EN 16931 rules for sums of money

Related questions

This is not legal advice. Sources: Act No. 222/2004 Coll. on VAT, Slovak Financial Administration e-invoicing FAQ, OpenPeppol BIS Billing 3.0 and the Slovak e-Invoicing Centre’s internal validation model. Verified on 6 July 2026.