Accounting documents

Credit note in Bulgaria: how to reduce the taxable amount of an invoice you already issued

A customer returns goods, you agree a discount after the invoice went out, or a deal simply falls through. A credit note is the document that fixes the taxable amount without touching the original invoice.

← Blog · 13 February 2026

What a credit note is

A credit note (in Bulgarian, кредитно известие) is a primary accounting document that reduces the taxable amount of an invoice you already issued. It does not cancel the invoice, it corrects it: a new document is attached to the original one, stating that the amount charged earlier was too high and by how much it needs to come down.

The taxable amount is the sum VAT (value added tax, ДДС in Bulgarian) is calculated on. NRA (the National Revenue Agency, НАП in Bulgarian) is the authority your company reports sales and VAT to. Once the base of an already invoiced sale needs to drop, the law does not let you simply edit the old invoice. A separate document showing the change is mandatory.

In everyday accounting talk, a credit note is sometimes called a "storno invoice" (сторно фактура), even though that is not the official legal term. Both phrases describe the same thing: a document that reduces an amount already charged.

A credit note is the mirror image of a debit note, which increases the taxable amount instead. Both exist because an invoice, once issued, is never rewritten, only corrected by a follow-up document.

When you need to issue a credit note

The trigger is always an event that happens after the original invoice and moves the agreed amount downward. For a small business, the most common cases are these.

A customer returns goods, in full or in part, after already receiving an invoice for the purchase.
A discount or rebate is agreed after invoicing, for example an annual volume bonus that was not known at the time of the first invoice.
A deal falls through entirely after an invoice has already been issued, for example a customer cancels a service before using it.
The price changes after delivery, for example due to a complaint or renegotiated terms.
A billing error is found where the original invoice charged more than was actually owed, and you need to correct the overcharge.

In every one of these cases, the original invoice stays exactly as issued in your books. The credit note is a separate document that supplements it, it never replaces or deletes it.

What a credit note must contain

A credit note is a primary accounting document and carries the same mandatory fields as any such document: name and number, issue date, supplier and customer details, and the reason for issuing it. One requirement, though, sets it apart from a plain invoice.

A mandatory reference to the number and date of the original invoice the note corrects. Without that link, the document does not work as a correction.
A short description of the reason: returned goods, a discount, a cancelled deal, or another cause for the reduction.
The amount by which the taxable base is reduced, and the corresponding reduction in charged VAT, if the original sale was subject to VAT.
Credit notes follow the same sequential numbering series as your company's invoices, not a separate series of their own. The note's number simply continues on from your invoice numbering, it does not restart.

In practice, most invoicing software, FreeMe.bg included, generates the credit note directly from the original invoice and fills in the reference automatically, so the risk of a missing link is minimal.

How a credit note shows up in your VAT records

If the original sale carried VAT, a credit note affects both sides of the deal, not just the supplier.

The supplier (the one issuing the note) reduces the amount of charged VAT for that tax period in their sales ledger (дневник за продажбите). That means less VAT owed to the state for the period the note was issued in.
The customer, if VAT registered and if they had already claimed input VAT credit on the original invoice, must correspondingly adjust their purchase ledger (дневник за покупките). The input VAT credit previously claimed on that portion of the amount is reduced.
Both adjustments happen in the period the credit note is issued, not retroactively in the period of the original invoice. The original VAT return is never reopened.
If the original sale was not subject to VAT at all, for example because the supplier is not VAT registered, the credit note simply corrects the invoiced amount with no effect on VAT ledgers.

Because both sides need to adjust their ledgers in sync, a credit note is a document the supplier is legally required to hand to the customer, not just an internal note.

Deadline to issue it, and how it differs from a debit note

The law sets a clear deadline: a credit note must be issued within 5 days of the event that triggers the change, for example the date goods were returned or the date a discount was agreed, not the date of the original invoice.

Missing that deadline does not remove the obligation to issue the note, but it creates exposure in an NRA audit if the ledger correction lags behind the actual event.
A debit note does the opposite job: it increases the taxable amount of an already issued invoice, for example for an additional charge, an extra service added to an already invoiced delivery, or a correction where the original amount was too low. It requires the same mandatory fields and the same 5-day deadline.
Both documents, credit and debit notes, count as primary accounting documents on equal footing with the invoice itself, and both share the same sequential numbering.

For a small business owner, the practical rule is simple: whenever an already invoiced amount changes, in either direction, document it with a note right away instead of waiting for the next reporting period.