How to Validate IBANs in Excel
One mistyped digit in an IBAN and a payment bounces — or worse, goes somewhere it shouldn't. Every IBAN carries a checksum precisely so software can catch that, but Excel has no built-in way to run it. Here's how.
Last updated: September 2026
| IBAN | Valid? | Country | |
|---|---|---|---|
| GB82 WEST 1234 5698 7654 32 | → | Yes | GB |
| DE89 3704 0044 0532 0130 01 | → | No | DE |
Method 1 — a formula
The mod-97 check means rearranging the string, mapping each letter to a two-digit number, and taking a 30-plus-digit number modulo 97 — which overflows Excel's precision, so you need a piece-by-piece MOD loop or a VBA function. Workable, but long and easy to get subtly wrong.
Method 2 — the 1-click way (Tellsheet)
IBAN Validate
Select the IBAN column and run IBAN Validate. It applies the official mod-97 checksum (plus a per-country length check), adds a Valid? column flagging every bad entry, a neatly space-grouped version, and the country code. Fully offline — the check is pure arithmetic, so nothing leaves your machine. Pairs with Validate Data and Check-Digit Validator (for barcodes and ISBNs).
Frequently asked questions
How do I validate an IBAN in Excel?
Run the mod-97 checksum — or let IBAN Validate do a whole column in one click.
Can Excel catch a mistyped account?
Not natively; IBAN Validate flags any that fail the checksum or length check.
Does it work offline?
Yes — it's pure arithmetic; nothing is sent anywhere.
What else does it add?
A formatted version and the 2-letter country code.
Related Excel guides
Catch a bad IBAN before it bounces
IBAN Validate runs the mod-97 checksum on your whole column — offline, in one click.
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