IBAN Generator

Calculate your German IBAN from bank code and account number

Calculate IBAN

Enter the bank code (BLZ) and account number

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The IBAN calculation runs exclusively in your browser. No data is transmitted to any server.

How is the IBAN calculated?

A German IBAN is composed of four components: the country code "DE", a two-digit check digit, the eight-digit bank code (BLZ) and the account number padded to 10 digits. Our generator automatically computes the correct check digit according to the international ISO 7064 standard.

The IBAN calculation is mathematically unambiguous: every valid combination of BLZ and account number yields exactly one IBAN. This calculation is standardized and recognized worldwide by banks and payment providers.

Structure of a German IBAN

A German IBAN always has exactly 22 characters and follows this pattern:

  • DE Country codeIdentifies Germany according to ISO 3166-1
  • XX Check digitTwo digits enabling error detection
  • 8 digits Bank codeUniquely identifies the bank
  • 10 digits Account numberPadded with leading zeros

The MOD-97 algorithm

The check digit is calculated using the MOD-97 procedure (ISO 7064). This algorithm can detect up to 98% of all input errors - including digit transpositions, single-digit errors and many multi-digit errors.

The calculation works in four steps:

  1. Build the BBAN: bank code (8 digits) + account number (10 digits with leading zeros)
  2. Append the country code: BBAN + "DE00" (where D=13, E=14 as numbers)
  3. Numeric conversion: letters are replaced by their numeric values (A=10, B=11, ... Z=35)
  4. Compute the check digit: 98 minus (numeric value MOD 97) = check digit
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Important note

Always compare the generated IBAN with your official bank documents. This calculation does not replace official confirmation by your bank.

Step-by-step example

We walk through the IBAN calculation using BLZ 37040044 (Commerzbank Cologne) and account number 532013000.

Step 1: Build the BBAN

Bank code: 37040044
Account number: 532013000 → padded with a leading zero: 0532013000
BBAN = 370400440532013000

Step 2: Append the country code

BBAN + "DE00" = 370400440532013000DE00
Replace the letters: D=13, E=14
Result: 370400440532013000131400

Step 3: Compute MOD 97

370400440532013000131400 MOD 97 = 9
Check digit = 98 - 9 = 89

Step 4: Assemble the IBAN

DE + check digit + BBAN
DE89 3704 0044 0532 0130 00

When do I need an IBAN generator?

There are several situations where you need to calculate your IBAN from a bank code and account number.

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Old records

You only have old account statements or documents with an account number and BLZ but no IBAN? Our generator computes the correct IBAN in seconds.

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No bank card to hand

Your debit card is not available but you know your BLZ and account number by heart? Generate your IBAN directly here without accessing online banking.

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Filling in forms

Many forms and online services ask for the IBAN. If you only have the old account details, our tool computes the full IBAN including check digit.

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Cross-check account data

Received an IBAN and want to check it matches a given BLZ and account number? Generate the IBAN and compare.

Avoid common mistakes

Watch out for these typical pitfalls when generating an IBAN.

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Leading zeros in the account number

Short account numbers are automatically padded with leading zeros to 10 digits. Account number "12345" becomes "0000012345". Make sure you do not enter any zeros twice.

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Outdated bank code

Bank codes can change through mergers. Use our bank search to find the current BLZ of your bank before generating the IBAN.

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Sub-account numbers

Some banks use sub-account numbers (for example for savings accounts). These are often not part of the standard account number. Use the main account number without any sub-account suffix.

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Don't confuse BLZ and account number

The BLZ always has exactly 8 digits, the account number a maximum of 10. Make sure to enter both values in the correct fields.

Frequently asked questions about the IBAN generator

Answers to the most important questions about IBAN calculation.

Is the generated IBAN correct?

Yes, our generator uses the official MOD-97 algorithm according to ISO 7064. The check digit is calculated with mathematical precision. We still recommend comparing the generated IBAN with your bank documents.

Does the generator also work for other countries?

Our generator is optimized specifically for German IBANs (DE). Other countries have different IBAN structures and check procedures. For non-German IBANs, please contact your bank.

Is my account data stored?

No, the entire calculation runs locally in your browser. Your bank code and account number are never sent to any server. There is no logging of your input.

What if my account number has fewer than 10 digits?

That is normal - many account numbers have only 7-9 digits. Our generator automatically pads them with leading zeros to 10 digits. "1234567" becomes "0001234567".

Why is a bank name shown to me?

Our generator cross-references the entered BLZ against the Bundesbank database. If the BLZ is found, we display the bank name as confirmation so you can see immediately whether the BLZ is correct.

Can I use the generated IBAN immediately?

Yes, the generated IBAN can be used for transfers right away - provided the input data (BLZ and account number) is correct. We recommend a one-time verification with your bank documents.

What is MOD-97?

MOD-97 is a mathematical algorithm (modulo 97) used for the IBAN check digit. It detects single digit errors and most transpositions. The standard is defined in ISO 7064.

How do I find my bank code?

You can find the BLZ on your debit card, on account statements or in online banking. Alternatively use our bank search - just enter the bank's name.

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