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RF Reference Calculator
Generate or validate an SEPA structured creditor reference (RF…).
Enter a reference number and click Generate, or paste an RF reference and click Validate.
How it works?
The RF Creditor Reference is an international structured reference format defined in ISO 11649 (2008). It starts with RF followed by two check digits, then up to 21 alphanumeric characters of your own reference. The total length is at most 25 characters.
The check digits are calculated using modulo-97 arithmetic — the same algorithm used for IBAN bank account numbers. The reference and the letters "RF00" are rearranged, all letters are replaced by their numeric equivalents (A=10, B=11 … Z=35), and the check digits are set so that the entire string divides by 97 with a remainder of 1.
The RF reference is designed for automated reconciliation: banks and accounting systems can verify that the reference has not been corrupted in transit, and match the payment to the correct invoice automatically.
Frequently asked questions
What is an RF creditor reference?
An RF creditor reference (ISO 11649) is a standardised payment reference used on SEPA credit transfers. It starts with the letters RF, followed by two check digits, followed by your own reference number (up to 21 alphanumeric characters). The check digits let banks and accounting systems verify the reference automatically and reduce manual reconciliation work.
Where is the RF reference used?
The RF reference is supported across the SEPA payment area — 36 European countries. It is widely used in Finland, the Nordic countries, and the Baltic states for invoicing and B2B payments. When your customer pays an invoice, they include the RF reference in the payment details so you can automatically match the incoming payment to the correct invoice in your accounting system.
What characters can I use in my reference?
The base reference (the part after RF and the two check digits) may contain digits 0–9 and uppercase letters A–Z. Spaces, hyphens, and other special characters are not allowed inside the reference itself — but the final RF reference may be displayed with spaces every 4 characters for readability (the grouped format). The total reference including RF and check digits must not exceed 25 characters, so your base reference can be at most 21 characters.
How are the check digits calculated?
The ISO 11649 check digit algorithm works as follows: (1) append "RF00" to your base reference; (2) replace each letter with its numeric value (A=10, B=11, … Z=35); (3) calculate the remainder when this large number is divided by 97; (4) subtract the remainder from 98 — the result (padded to two digits) is your check sum. To validate, rearrange the reference by moving the first four characters (RF + check digits) to the end, convert letters to numbers, and check that the result divides evenly by 97 with remainder 1.
What is the difference between the grouped and continuous formats?
Both formats contain identical information — the only difference is spacing. The grouped format (e.g. RF18 1234 5678) splits the reference into blocks of 4 characters with spaces, making it easier to read and verify visually. It is recommended for printing on invoices. The continuous format (e.g. RF1812345678) has no spaces and is suitable for electronic data entry, database storage, or copying into payment systems.