data tool
IBAN checker
An IBAN is valid in format when it has the right length for its country and its two check digits pass the mod 97 test. Paste one IBAN or a list and the checker confirms both, shows the number in groups of four, and splits out the bank code, branch and account number for 89 countries.
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- Runs on your device, nothing is uploaded
- Free, no sign in
- No watermark, no file limit
How it works
- 1
Paste the IBAN
With or without spaces, in capitals or not. Paste a whole list to check many at once.
- 2
Read the verdict
Green means the length and check digits are right for that country; red says exactly what is wrong.
- 3
Check the parts
The bank code, branch or sort code and account number are split out, so you can match them against the bank details you were given.
- 4
Copy the results
Copy all results as a list, one IBAN per line with valid or the reason it failed.
What mod 97 proves and what it does not
The two digits after the country code are check digits, calculated so that the whole IBAN passes a simple test. Move the first four characters to the end, turn every letter into a number from 10 to 35, and the resulting number divided by 97 must leave a remainder of 1. A single wrong character or two swapped neighbours always fails that test, which is why IBANs catch most typing mistakes before money is sent. What it cannot prove is that the account exists or belongs to the name on the invoice; only the bank knows that.
Length by country
Every country sets a fixed IBAN length. The United Kingdom and Ireland use 22 characters, Germany 22, France 27, Italy 27, Spain 24, the Netherlands 18, Belgium 16 and Norway 15, the shortest. The checker compares the length against the country's structure first, because a missing or extra character is the most common error and the message is clearer than a failed check digit. The country structures here follow the IBAN registry for 89 countries.
Reading the parts
After the country code and check digits comes the BBAN, the domestic account number. Its layout differs by country: in the UK it is a four letter bank code, a six digit sort code and an eight digit account number; in Germany an eight digit bank code and a ten digit account; in France a bank code, a branch code, an account number and a two digit key. Seeing these parts makes it easy to compare an IBAN with the sort code and account number a supplier gave separately.
Printing an IBAN on an invoice
Print the IBAN in groups of four, which is the printed format the standard recommends because it is easier to read and copy. Show it with the account name and the bank's BIC or SWIFT code for international payments. In the EU the SEPA rules mean euro payments within the area need only the IBAN. Checking the IBAN before the invoice goes out avoids a payment bouncing days later, which is slow and sometimes costs a fee to return.
Bank details on quotes and invoices
Invoices made in the proposals module show bank details for payment, and invoices can also carry a pay link that opens a public page with the amount due and the bank details, plus card payment through Stripe on paid plans. Whichever way you send them, check the IBAN here first, then copy it from the formatted result rather than retyping it.
Payment fraud
Fraudsters often send convincing emails asking a business to update a supplier's bank details. A changed IBAN passes every format check, because it is a real account, just not the supplier's. Confirm any change of bank details by phoning a number you already hold for the supplier, never one from the email asking for the change.
Limits
- A valid IBAN has a correct format and check digits; it can still belong to a closed account or the wrong person.
- The country structures come from the IBAN registry as of its December 2024 release. A country added later is reported as not in the table.
- No bank name lookup: that needs a bank directory, which would mean sending the number somewhere.
- National check digits inside some BBANs, such as France's RIB key, are shown but not separately verified.
What it does not do
- It does not confirm who owns the account.
- It does not send the IBAN to any service.
- It does not store the numbers.
Questions people ask
How do I check if an IBAN is valid?
Paste it here. The checker confirms the country code is known, the length is right for that country and the check digits pass the mod 97 test. If all three hold, the IBAN is valid in format. It does not prove the account exists, which only the bank can confirm.
Does a valid IBAN mean the account exists?
No. Format and check digits catch typing mistakes, but a correctly formed IBAN can belong to a closed account, a different person or a fraudster. Before paying a new supplier or a changed account, confirm the details by phone using a number you already trust.
How long is an IBAN in the UK and Ireland?
Twenty two characters in both: two letters for the country, two check digits, a four letter bank code, a six digit sort code and an eight digit account number. Printed in groups of four, a UK IBAN reads like GB82 WEST 1234 5698 7654 32.
Do Australia and the United States use IBANs?
No. Australia uses a BSB and an account number, and the United States uses a routing number and an account number. To receive money from Europe, they give the payer a SWIFT or BIC code with their domestic details instead. Only countries in the IBAN registry have IBANs.
Why does a correct looking IBAN fail the check?
Usually one character is wrong, two neighbouring characters are swapped, or a letter O was typed for a zero. The check digits are designed to catch exactly these mistakes. Copy the IBAN from the original document again rather than retyping it, and compare the parts shown here.
Put the checked details on an invoice
Take what you made here into proposals.
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Background reading: the question page on this.
Written and checked by the OneCraft team. Last checked .