# Bulgaria IBAN Validator & BIC Bank Code Checker (BNB)
> Instant MOD-97 validation for 22-character Bulgarian IBANs with 4-letter BIC bank code extraction; Bulgarian accounts settle in EUR since the 1 January 2026 euro adoption.

- **Canonical URL:** https://stanzaapi.com/tools/iban-validator/country/bulgaria-bg
- **Governing Standard:** ISO 13616 / ISO 7064 MOD-97-10 (SWIFT & ISO 13616 IBAN Registry)
- **Latency:** <1ms Edge
- **Privacy:** In-memory execution only (zero data stored or logged)

## Technical Overview & Governing Rules
In Bulgaria, the International Bank Account Number (IBAN) has a fixed length of 22 alphanumeric characters starting with the two-letter ISO 3166-1 alpha-2 country code 'BG', followed by two MOD-97 check digits.

The National Basic Bank Account Number (BBAN) follows the official pattern: 4a6n8c. The national bank code is located at BBAN character offset [0:4]. The branch identifier is at offset [4:8].

National IBAN transfers in Bulgaria (BG) are settled in EUR.

Validation computes the ISO 7064 Modulo-97-10 checksum by transposing the first 4 characters to the end, converting letters to numeric digits (A=10, ..., Z=35), and calculating arithmetic integer modulo 97 (must equal 1).

A Bulgarian IBAN is 22 characters: BG, two MOD-97 check digits, and an 18-character national BBAN in the pattern 4a6n8c — a 4-letter bank code (the first four letters of the bank BIC), 6 digits, and an 8-character account.

Bulgaria adopted the euro on 1 January 2026 at the irrevocable rate of 1.95583 BGN per EUR, so Bulgarian IBAN transfers now settle in EUR rather than BGN.

## Specification Matrix
| Attribute | Value | Description |
| --- | --- | --- |
| Country Code | BG | ISO 3166-1 alpha-2 |
| Total IBAN Length | 22 characters | Fixed standard length |
| BBAN Format | 4a6n8c | National structure (n=numeric, a=alpha, c=alphanumeric) |
| SEPA Zone | Yes (Single Euro Payments Area) | SEPA compliance status |
| Currency (ISO 4217) | EUR | National settlement currency |
| Bank Code Position | BBAN Offset 0 (4 chars) | National clearing code |
| Branch Code Position | BBAN Offset 4 (4 chars) | Branch identification |
| BIC Bank Code | BBAN offset 0 (4 letters) | First four letters of the bank BIC |
| Settlement Currency (2026) | EUR | Euro adopted 1 January 2026; 1.95583 BGN = 1 EUR |

## Standard JSON Response Model
```json
{
  "valid": true,
  "iban": "BG80BNBG96611020345678",
  "countryCode": "BG",
  "countryName": "Bulgaria",
  "length": 22,
  "bban": "4a6n8c",
  "sepa": true,
  "checksumValid": true,
  "bankCode": "XXXX"
}
```

## Frequently Asked Questions & Edge Cases
### Q: How many characters is an IBAN in Bulgaria?
**A:** An official IBAN in Bulgaria (BG) is exactly 22 characters in length. Any shorter or longer value fails ISO 13616 validation.

### Q: Is Bulgaria part of the SEPA payment network?
**A:** Bulgaria is a member of the Single Euro Payments Area (SEPA), enabling low-cost euro bank transfers.

### Q: What currency are Bulgaria IBAN transfers settled in?
**A:** IBAN transfers for Bulgaria (BG) settle in EUR, the national settlement currency. Cross-border SEPA transfers to Bulgaria may still be denominated in EUR where both banks support the scheme.

### Q: How is the MOD-97 check digit calculated for BG IBANs?
**A:** The first 4 characters are moved to the end, letters are converted to numbers (A=10 to Z=35), and the resulting number is evaluated with modulo 97 arithmetic. A valid IBAN yields a remainder of exactly 1.

### Q: What currency do Bulgarian IBAN transfers settle in?
**A:** Bulgaria adopted the euro on 1 January 2026 at the fixed rate of 1.95583 BGN per EUR, and since 1 February 2026 the euro is the sole legal currency. Bulgarian IBAN transfers therefore settle in EUR.

### Q: What is the 4-letter bank code in a Bulgarian IBAN?
**A:** A Bulgarian IBAN is 22 characters: BG, two check digits, a 4-letter bank code (the first four letters of the bank BIC), 6 digits, and an 8-character account. The bank code is the four letters at BBAN offset 0.