IBAN validator
Check an IBAN's validity, format the number and compute its check digits.
Compute check digits (generate IBAN)
Validation applies the ISO 13616 mod 97 algorithm and checks the per-country length. A structurally valid IBAN does not guarantee the account exists; only the bank can confirm that.
Built by
Miguel Ángel Colorado Marin (MACM)
Built by
Miguel Ángel Colorado Marin (MACM)
Full-Stack Developer · Guadalajara, España
I develop web apps, digital tools and full projects — from design to deployment.
A mistyped IBAN is the usual reason a transfer bounces, and the check digits exist precisely to catch it before sending. This tool applies the ISO 13616 mod 97 rule: it moves the first four characters to the end, converts letters to numbers and checks that the remainder is 1. It also verifies the expected length for each country, shows the detected country and computes the check digits from the BBAN, useful when you generate or verify test accounts.
Features
- ✓Validation with the ISO 13616 mod 97 algorithm
- ✓Expected length check per country
- ✓Country identification and IBAN formatting in groups of four
- ✓Check-digit generator from the BBAN
- ✓All local: the IBAN is not sent to any server
How do I validate and generate an IBAN?
- 1
Type the IBAN
Paste the IBAN with or without spaces; it normalizes to uppercase without separators.
- 2
Check the result
You get whether it is valid, the country, the length and the check-digit status.
- 3
Generate from the BBAN
Pick the country, paste the BBAN and get the full IBAN with the correct check digits.
- 4
Copy the result
Click the generated IBAN to copy it formatted in groups of four.
Frequently asked questions
How does the mod 97 validation work?
The first four characters of the IBAN are moved to the end, each letter is replaced by its numeric value (A=10, B=11…), a huge number is formed and its remainder when divided by 97 is calculated. A correct IBAN gives exactly 1.
What does it mean for an IBAN to be valid?
It means the structure, the length for that country and the check digits are correct. It does not guarantee that the account exists or is active: only the owning bank can confirm that.
Can I compute an account's check digits?
Yes. Enter the country and the BBAN (the account number without the country code or the check digits) and the tool computes the two correct digits and builds the full IBAN. It is useful to generate test data.
Is my IBAN sent anywhere?
No. The check is a local calculation in your browser. The IBAN is neither transmitted nor stored.
Related tools
Embed IBAN Validator on your site
Add IBAN Validator to any web page with a simple iframe. Free, with attribution to miguelacm.es.
<iframe
src="https://miguelacm.es/embed/iban-validator"
width="100%"
height="700"
frameborder="0"
title="IBAN Validator — miguelacm.es"
></iframe>