Early access. Product screens use synthetic demo data; accounts and bank imports are not open yet. What is live today

Live

Check a payment reference before your customer pays

Validate an RF creditor reference, create one from your invoice number, and test whether a remittance text stays within the SEPA character set and 140-character limit. The tool also shows whether our reconciliation matcher would still find your invoice reference. Everything runs in your browser.

By Daniel Malbašić · Last reviewed

1. Check an RF creditor reference

RF + 2 check digits + up to 21 letters or digits. Spaces are ignored.

Type or paste a reference to check it.

2. Generate an RF reference from your invoice number

Up to 21 letters/digits after separators are removed.

Enter a base reference to calculate the check digits.

3. Will the reference survive the transfer and be found?

0 / 140 characters (unstructured remittance limit)

Enter a remittance text and your invoice reference.

Everything runs in your browser; nothing you type is sent or stored. The checker tests format and our own matching rule. It cannot tell you what a particular bank or payer app will do with the text.

Short answer

A SEPA transfer reference checker tests whether a payment reference will arrive in a usable form. This one validates ISO 11649 RF creditor references with the mod 97 check, generates an RF reference from your invoice number, flags characters outside the SEPA basic Latin set and text over 140 characters, and shows whether our reconciliation matcher would still recognise your invoice reference.

What does this SEPA transfer reference checker check?

The tool above has three parts. Each answers a different question you have before a customer pays:

Part Question it answers Rule applied
1. Check an RF reference Is this RF creditor reference well formed? ISO 11649: "RF", two check digits, up to 21 letters or digits; MOD 97-10 remainder must be 1
2. Generate an RF reference What RF reference belongs to my invoice number? Check digits = 98 − (remainder of the reference + "RF00")
3. Remittance text check Will the text survive the transfer and still be found? EPC character set, 140-character limit, slash rules, and the DIGITAL EUR matching rule

Everything runs in your browser. Nothing you type is sent or stored.

What is an RF creditor reference?

An RF creditor reference, also called the Structured Creditor Reference, is an international format for the payment reference on an invoice, defined in ISO 11649. It has three parts:

  • the letters RF;
  • two check digits, which catch typing errors;
  • the reference itself: 1 to 21 letters or digits chosen by the creditor, usually derived from the invoice or customer number.

The whole reference is at most 25 characters. On paper it is printed in groups of four (RF18 5390 0754 7034); in electronic payment files it has no spaces (RF18539007547034). The European Payments Council's SEPA Credit Transfer rulebook recommends the RF reference for structured remittance information. Finland and Slovenia, among others, use it in domestic payments; Finland has accepted RF references that are not built from the Finnish national reference since 18 November 2024.

How are RF check digits calculated and validated?

The method is the same MOD 97-10 arithmetic used for IBAN check digits.

To generate the check digits:

  1. Take the reference and remove spaces and separators: INV-2026-0042 becomes INV20260042.
  2. Append RF00.
  3. Replace letters with numbers: A = 10, B = 11 … Z = 35. R = 27, F = 15.
  4. Divide by 97 and take the remainder.
  5. Check digits = 98 − remainder, written with two digits (a leading zero if needed).

Worked example from ISO 11649. Reference 2348231 → append RF00 → 2348231RF00 → replace letters → 2348231271500. The remainder after dividing by 97 is 27, and 98 − 27 = 71. The RF reference is RF71 2348 231.

To validate an RF reference, move the first four characters to the end, replace letters with numbers and divide by 97. The remainder must be exactly 1. For RF712348231: 2348231 + RF71 → 2348231271571, remainder 1, valid.

Two published examples that do not pass

While testing we recomputed every example we found. Two widely copied ones fail the check:

  • RF68 5390 0754 7034, printed in the ISO 11649 sample pages, leaves a remainder of 51. The correct check digits for that reference are 18: RF18 5390 0754 7034.
  • RF99 1234 5675, from an older Finnish banking guide, leaves a remainder of 96; the correct form is RF04 1234 5675.

Use the generator rather than copying examples, and test any reference format with a few real invoice numbers before printing it on invoices.

Receiving banks are not required to check the RF check digits, so a wrong reference can travel all the way to your bank statement. That is why it is worth checking on your side, before the invoice goes out.

Which characters can a SEPA payment reference contain?

The EPC implementation guidelines for SEPA Credit Transfer (2025 version) list the characters that all banks and their customers must be able to support:

Allowed Characters
Letters a–z, A–Z
Digits 0–9
Symbols / - ? : ( ) . , ' +
Space the normal space character

The underlying ISO 20022 messages allow far more (UTF-8), and banks may agree to support extra characters, for example national letters. But anything outside the basic set is not guaranteed to arrive unchanged. Umlauts (ä, ö, ü), ß, accented letters, &, #, @, €, underscores, semicolons and long dashes copied from word processors are the usual problems. Some software converts them (for example ä to ae or a); some removes them; some rejects the payment form.

Slash rules for references

For references and identifiers, such as the end-to-end ID or a structured creditor reference, the guidelines add three rules: use only the basic set, do not start or end with /, and do not use //. The checker warns about these when you enter your invoice reference.

How long can SEPA remittance information be?

Field Maximum Notes
Unstructured remittance information (free text) 140 characters One occurrence; what most payers type in the "reference" box
Structured remittance information 140 characters including the inner tags Used for the RF creditor reference
Creditor reference inside the structured block 35 characters An RF reference uses at most 25
End-to-end identification 35 characters Set by the payer's software and passed on unchanged

A payment carries either the unstructured or the structured form, not both. The rulebook requires banks to pass remittance information on in full and without alteration. In practice the risk sits earlier: a payer's banking app may have a shorter field, may cut long text, or may strip characters before the payment is created. The checker's "worst case" line simulates that by removing characters outside the basic set and cutting the text at 140 characters.

Will a reconciliation matcher find your reference?

The last part of the tool runs the exact matching function used in the DIGITAL EUR reconciliation demo, imported from the same code. Its rules are strict on purpose:

  • The invoice reference must contain at least four letters or digits; shorter references are ignored.
  • Matching is case-insensitive and ignores separators between the letter and digit groups, so INV-2026-0042 is found in inv 2026/0042 and in INV20260042.
  • Only complete references count. INV-12 is not found inside INV-123, so a short reference cannot accidentally match a longer one.

A found reference is one piece of evidence (it adds 65 points in the demo's transparent scoring); amounts, IBAN and name add or subtract more, and every suggestion still needs human approval. The SEPA reconciliation guide explains the full process, and the reconciliation product page explains how the evidence is shown.

Example

Your invoice reference is INV-2026-0042. A customer types: Rechnung INV-2026-0042 – Müller & Söhne.

  • Length: 39 characters, within the limit.
  • Outside the basic set: the long dash, ü, & and ö. Expect these to be changed or removed.
  • Matcher, text as typed: reference found.
  • Worst case: reference still found, because the problem characters are not inside the reference.

Now imagine the reference had been written INV_2026_0042 on the invoice. Underscores are not in the basic set; if an app removes them, the payer's text becomes INV20260042, which our matcher still finds, but a stricter system looking for the exact string would not.

Common errors

  1. Copying a reference with a typographic dash (– instead of -). It looks identical, but the dash is outside the basic set.
  2. References that are too short or too generic, such as 123 or Invoice. They cannot be matched reliably.
  3. Long free text before the reference. If the payer's app cuts the text, the reference at the end is the part that disappears. Put the reference first.
  4. Leading zeros dropped by the payer. 0042 typed as 42 is a different reference. An RF reference makes this detectable, because the check digits will no longer match.
  5. Printing an RF example from documentation without recomputing the check digits.

What this checker does not do

It does not contact any bank or know a specific bank's field lengths, and it does not validate national reference formats (for example Finnish, Slovenian SI or Belgian structured communications) beyond the RF standard. It cannot tell you whether a payment was made. For IBAN checks, use the IBAN format checker.

Frequently asked questions

What is an RF reference?

It is an international payment reference standardised in ISO 11649: "RF", two check digits and up to 21 letters or digits. Creditors print it on invoices so that payers can copy it into the payment and the creditor can match the payment automatically.

Why is my RF reference invalid?

Most often because of a typo, a copied example with wrong check digits, characters other than letters and digits, or a reference longer than 21 characters after "RF" and the check digits. The checker shows which check digits your reference would need.

Are lower-case letters allowed in an RF reference?

The standard treats lower-case letters the same as upper case when calculating the check digits. The checker converts everything to upper case, which is the safer way to print it.

Can I use umlauts or special characters in a SEPA payment reference?

Only the basic Latin set is guaranteed: letters a–z and A–Z, digits, space and / - ? : ( ) . , ' +. Other characters may be converted, removed or rejected along the way.

What happens if the reference is longer than 140 characters?

The unstructured field allows at most 140 characters. Banking apps usually stop you typing more or cut the text; either way, anything after the limit is lost. Keep the reference short and first.

Is my data sent anywhere?

No. The checks run in your browser and nothing is stored.

Does the payer's bank check the RF check digits?

It is not required to. That is why you should check references before you send the invoice, not after the payment arrives.

Sources