Bank of Ireland (BOI) IBAN Calculator
Enter your BOI sort code and account number to generate an Irish IBAN (IE format).
Validate Any IBAN
Paste an IBAN below to verify if its checksum is mathematically valid (mod 97 check).
What this BOI IBAN calculator does
This tool helps you generate a Bank of Ireland IBAN from two common details: your sort code and your account number. It is designed for Irish-format BOI accounts where the IBAN starts with IE and includes the BOI bank code BOFI.
It also includes a built-in IBAN validator so you can check whether an IBAN passes the official checksum formula. That validation confirms the number is structurally valid, but it does not guarantee that the account is open or able to receive payments.
Why IBAN matters
An IBAN (International Bank Account Number) standardizes bank account details for domestic and international transfers, especially in SEPA payments across Europe. Using a correct IBAN reduces failed payments, avoids delays, and helps ensure your transfer reaches the intended account.
- Used for salary, bill, and transfer payments
- Critical for cross-border and SEPA transactions
- Includes checksum digits to catch typing mistakes
How BOI IBAN generation works
For Bank of Ireland (Ireland), the IBAN structure is typically:
IEkk BOFI ssssss cccccccc
- IE = country code
- kk = calculated check digits
- BOFI = Bank of Ireland identifier
- ssssss = 6-digit sort code (branch code)
- cccccccc = 8-digit account number
Step-by-step checksum logic
The checksum digits are not random. They are produced using the ISO 13616 / MOD 97-10 method:
- Build BBAN: BOFI + sort code + account number
- Place country code and placeholder checksum at the end (IE00)
- Convert letters to numbers (A=10, B=11, ..., Z=35)
- Compute remainder when divided by 97
- Checksum = 98 - remainder
If the final IBAN gives remainder 1 when run through the same process, it passes checksum validation.
Common mistakes to avoid
- Entering fewer than 6 digits for sort code
- Forgetting leading zeros in account numbers
- Mixing old local account formats with IBAN format
- Assuming checksum validity means the account definitely exists
Best practices before making payments
Even with a valid IBAN, always confirm recipient details with a trusted source. If you are paying a new recipient, verify account information independently and watch for invoice fraud or last-minute account change requests.
- Double-check beneficiary name and IBAN together
- Send a small test payment first when appropriate
- Keep records of confirmation messages and invoices
FAQ
Does this calculator work for all Irish banks?
The generator is specifically configured for Bank of Ireland with the BOFI bank code. The validator, however, can check the checksum of any IBAN string.
Can I use this for UK BOI accounts?
UK BOI accounts follow a different country structure (GB format), so this generator is focused on Irish-format BOI IBANs.
Is my data sent anywhere?
No. Everything on this page is calculated directly in your browser with JavaScript. There is no server-side processing in this demo page.
Final thoughts
A reliable BOI IBAN calculator saves time, reduces payment errors, and gives you confidence when preparing bank transfers. Use it as a quick formatting and checksum tool, then confirm account ownership details before sending funds.