# Andorra (AD) IBAN & Bank Routing Validator
> Instant sub-1ms ISO 13616 MOD-97 checksum validation, BBAN decomposition, and bank routing extraction for Andorra (AD) bank accounts.

- **Canonical URL:** https://stanzaapi.com/tools/iban-validator/country/andorra-ad
- **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 Andorra, the International Bank Account Number (IBAN) has a fixed length of 24 alphanumeric characters starting with the two-letter ISO 3166-1 alpha-2 country code 'AD', followed by two MOD-97 check digits.

The National Basic Bank Account Number (BBAN) follows the official pattern: 8n12c. The national bank code is located at BBAN character offset [0:4]. The branch identifier is at offset [4:8].

National IBAN transfers in Andorra (AD) 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).

## Specification Matrix
| Attribute | Value | Description |
| --- | --- | --- |
| Country Code | AD | ISO 3166-1 alpha-2 |
| Total IBAN Length | 24 characters | Fixed standard length |
| BBAN Format | 8n12c | 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 |

## Standard JSON Response Model
```json
{
  "valid": true,
  "iban": "AD00...",
  "countryCode": "AD",
  "countryName": "Andorra",
  "length": 24,
  "bban": "8n12c",
  "sepa": true,
  "checksumValid": true,
  "bankCode": "XXXX"
}
```

## Frequently Asked Questions & Edge Cases
### Q: How many characters is an IBAN in Andorra?
**A:** An official IBAN in Andorra (AD) is exactly 24 characters in length. Any shorter or longer value fails ISO 13616 validation.

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

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

### Q: How is the MOD-97 check digit calculated for AD 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.