# Strict numbering under Bulgarian VAT law: why an invoice is never deleted

Source: https://ood.bg/en/blog/strict-invoice-numbering-bulgarian-vat-law
Published: 2026-10-08 · Updated: 2026-10-08

## TL;DR
- An invoice number has 10 digits, no letters, in sequence with no gaps.
- An issued invoice is never edited or deleted — it is annulled and a new one is issued.
- In ood.bg the number is assigned on issue; drafts have no number.

## Key facts
- **Number:** 10 digits
- **Mistake:** annul
- **Draft:** no number

Under Bulgarian VAT law, invoices and credit/debit notes carry sequential 10-digit numbers with no gaps and no repeats. An issued document is never edited or deleted: if it is wrong, it is annulled and a new one is issued.

## What does the law require for numbers?

Numbers are sequential, 10 digits long, with no letters or other symbols. Invoices, credit notes and debit notes share one series. A skipped or repeated number is a breach that is easy to spot in an audit.

## What if I make a mistake on an invoice?

Corrections to issued invoices are not allowed. The wrong document is **annulled** and a new one is issued with the next number. The annulled document stays in the archive — nothing is deleted.

## How does ood.bg protect the numbering?

- Drafts have no number; it is assigned at the moment of issue.
- Annulment requires a reason and is written to the audit log.
- Numbering groups A–D let several offices issue in parallel from their own series without collisions.

Read more about documents in the [features](https://ood.bg/en/features#docs), and if you are switching programs, see how to [continue from your last number](https://ood.bg/en/integrations#import).

## FAQ

### Can I delete an issued invoice?

No. An issued invoice is annulled with a reason and a new one is issued; the annulled one stays in the archive.

### How many digits does a Bulgarian invoice number have?

10 digits, no letters, in an unbroken sequence.

### Can I continue the numbering from my old program?

Yes. In ood.bg you set a starting number and the series continues without gaps or duplicates.

## Sources
- [National Revenue Agency (NRA)](https://nra.bg)