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IBAN checker and validator: structure, length and checksum

Enter an IBAN and see at once whether length, characters and checksum are right. The check runs in your browser and your input is not sent anywhere. The result says nothing about whether the account exists.

Validate an IBAN

Spaces and lower-case letters are fine. The check runs only in your browser; your input is not sent anywhere.

The result appears as soon as you enter an IBAN.

What the check establishes

The validator runs its checks in this order. First spaces are removed and lower-case letters are converted to capitals. Then it checks that only letters and digits occur and that the country code is known. Next it compares the length with the length defined for the country. Finally it calculates the checksum with the modulo 97 method: country code and check digits are moved to the end, letters are converted to numbers (A = 10 to Z = 35), and the resulting number must leave the remainder 1 when divided by 97.

What the check does not establish

A passed checksum only means that the IBAN is internally consistent. It does not say that a bank has issued it, that the account is open or that it belongs to the expected recipient.

Structure of a German IBAN

The 22 characters of a German IBAN, using the sample IBAN that appears in many bank and payment documentations. It passes format and checksum, but it is a documentation example and not meant for payments.

DE89 3704 0044 0532 0130 00

The 22 characters of a German IBAN
DE
Country code
89
Check digits
37040044
Bank code (Bankleitzahl)
0532013000
Account number
Country code DE
DE for Germany (ISO 3166)
Check digits 89
two digits, calculated with modulo 97
Bank code (Bankleitzahl) 37040044
8 digits; in a real IBAN the code of the bank
Account number 0532013000
10 digits, padded with zeros if the account number is shorter

Common error messages

  • Wrong length: a character is missing or doubled. A German IBAN always has 22 characters.
  • Invalid characters: usually the letter O instead of the digit 0, or a special character picked up when copying from a PDF.
  • Checksum does not match: often two swapped digits or one digit copied wrongly.
  • Unknown country: the country code is not in the list below.

IBAN length by country

IBAN length by country code
CountryCountry codeCharacters
AustriaAT20
BelgiumBE16
SwitzerlandCH21
CzechiaCZ24
GermanyDE22
DenmarkDK18
SpainES24
FinlandFI18
FranceFR27
United KingdomGB22
IrelandIE22
ItalyIT27
LiechtensteinLI21
LuxembourgLU20
NetherlandsNL18
NorwayNO15
PolandPL28
PortugalPT25
SwedenSE24
TürkiyeTR26

Testing without a real IBAN

Forms and software need IBANs that are guaranteed not to belong to any account. The test IBAN generator creates such values with a valid checksum. Wondering whether you also need a BIC? See SWIFT code vs BIC.

Frequently asked questions

Can I check here whether an IBAN exists?
No. The check finds typing errors and wrong lengths. Only the bank that holds the account knows whether it exists and accepts payments.
Is it safe to enter my IBAN here?
The calculation runs entirely in your browser and no request is sent to a server. If you want to be completely sure, check a sample IBAN, or leave out the last digits and add them for a test.
Do I have to remove spaces?
No. Spaces are removed and lower-case letters are converted before the check.
My bank rejects the IBAN but the validator says “fine”. Why?
The format is right, but the IBAN is not issued, the account does not accept that payment type, or bank code and account number do not belong together. Only the bank can clarify that.
Which countries does the validator support?
The 20 countries in the table below, which are the most common in German-speaking and neighbouring countries. For other countries the validator says that it does not know the country format.

Related tools

Sources and status

Content last reviewed: October 2026. Not legal or tax advice; the statements of the competent authorities prevail.