RF Creditor Reference Checker

The check digit proves the reference is internally consistent — that it was typed or copied without a slip. It does not mean the reference exists in any creditor’s system, or that a payment carrying it will reconcile. It is a structural check, the same kind IBAN gets, not a lookup.

Source: The RF structure and its checksum are the ISO 7064 MOD 97-10 family, the same one IBAN uses. ISO 11649 itself is a paid standard, so this project does not link or claim to hold it; the algorithm is implemented directly and self-proved against the standard’s own published example RF18 5390 0754 7034 — it validates, the implementation reproduces its check digits, and changing any character makes it fail.

The ISO 11649 structured creditor reference begins with the letters RF followed by two check digits. A value that does not start with RF is either a plain domestic reference, or an RF reference with its prefix lost.

Fix: If this is a domestic reference, it is not an RF reference; if the RF was dropped, restore it.

Source: The RF structure and its checksum are the ISO 7064 MOD 97-10 family, the same one IBAN uses. ISO 11649 itself is a paid standard, so this project does not link or claim to hold it; the algorithm is implemented directly and self-proved against the standard’s own published example RF18 5390 0754 7034 — it validates, the implementation reproduces its check digits, and changing any character makes it fail.

After the RF prefix the reference is drawn from A–Z and 0–9. Spaces are printed every four characters for readability and are ignored, but punctuation or other characters mean the value has been mangled or is not an RF reference.

Fix: Remove anything that is not a letter or digit and check the length.

Source: The RF structure and its checksum are the ISO 7064 MOD 97-10 family, the same one IBAN uses. ISO 11649 itself is a paid standard, so this project does not link or claim to hold it; the algorithm is implemented directly and self-proved against the standard’s own published example RF18 5390 0754 7034 — it validates, the implementation reproduces its check digits, and changing any character makes it fail.

The two characters after RF are check digits and must be numeric. Letters in those positions mean the value is not a well-formed RF reference — the reference body starts after them.

Fix: Check the two characters right after RF; they are the checksum, not part of the reference.

Source: The RF structure and its checksum are the ISO 7064 MOD 97-10 family, the same one IBAN uses. ISO 11649 itself is a paid standard, so this project does not link or claim to hold it; the algorithm is implemented directly and self-proved against the standard’s own published example RF18 5390 0754 7034 — it validates, the implementation reproduces its check digits, and changing any character makes it fail.

An RF reference is RF, two check digits, and a reference body of one to twenty-one characters — five to twenty-five characters in all. Outside that range it cannot be a valid RF reference; a body longer than twenty-one characters is the usual cause.

Fix: Trim or complete the reference body to between one and twenty-one characters.

Source: The RF structure and its checksum are the ISO 7064 MOD 97-10 family, the same one IBAN uses. ISO 11649 itself is a paid standard, so this project does not link or claim to hold it; the algorithm is implemented directly and self-proved against the standard’s own published example RF18 5390 0754 7034 — it validates, the implementation reproduces its check digits, and changing any character makes it fail.

Rearranged and run through the ISO 7064 MOD 97-10 checksum — the same one IBAN uses — the reference does not come out to a remainder of one. One of the characters is wrong, most often a transposition or a mis-keyed digit in the reference body, not necessarily in the check digits.

Fix: Re-read the reference from its source rather than trusting the expected check digits, since the error may be in the body.

Source: The RF structure and its checksum are the ISO 7064 MOD 97-10 family, the same one IBAN uses. ISO 11649 itself is a paid standard, so this project does not link or claim to hold it; the algorithm is implemented directly and self-proved against the standard’s own published example RF18 5390 0754 7034 — it validates, the implementation reproduces its check digits, and changing any character makes it fail.

The reference is internally consistent under the ISO 7064 MOD 97-10 checksum. That is the strongest statement possible about an RF reference without asking the creditor whose system issued it.

Source: The RF structure and its checksum are the ISO 7064 MOD 97-10 family, the same one IBAN uses. ISO 11649 itself is a paid standard, so this project does not link or claim to hold it; the algorithm is implemented directly and self-proved against the standard’s own published example RF18 5390 0754 7034 — it validates, the implementation reproduces its check digits, and changing any character makes it fail.

RF, then two check digits, then the reference body the creditor chose. The body is theirs to structure — it often wraps a domestic reference number — so this tool checks the RF envelope, not what the body means.

Source: The RF structure and its checksum are the ISO 7064 MOD 97-10 family, the same one IBAN uses. ISO 11649 itself is a paid standard, so this project does not link or claim to hold it; the algorithm is implemented directly and self-proved against the standard’s own published example RF18 5390 0754 7034 — it validates, the implementation reproduces its check digits, and changing any character makes it fail.

RF references are printed in groups of four for readability and are sometimes copied in lower case. Those are presentation and are normalised away before checking — but stored with spaces or in lower case, the reference will fail to match another system’s copy of it.

Fix: Store the reference as an unbroken run of capitals and digits.

Source: The RF structure and its checksum are the ISO 7064 MOD 97-10 family, the same one IBAN uses. ISO 11649 itself is a paid standard, so this project does not link or claim to hold it; the algorithm is implemented directly and self-proved against the standard’s own published example RF18 5390 0754 7034 — it validates, the implementation reproduces its check digits, and changing any character makes it fail.

An RF reference and an IBAN both start with two letters and two check digits and share the same checksum, which is why they get confused. But an RF reference identifies a payment, not an account, and it is at most 25 characters where an IBAN is up to 34 and starts with a country code, not RF.

Source: The RF structure and its checksum are the ISO 7064 MOD 97-10 family, the same one IBAN uses. ISO 11649 itself is a paid standard, so this project does not link or claim to hold it; the algorithm is implemented directly and self-proved against the standard’s own published example RF18 5390 0754 7034 — it validates, the implementation reproduces its check digits, and changing any character makes it fail.