Excel Tools

Validate IBANs, VAT numbers and tax IDs in bulk

Pick an Excel or CSV file, or paste a list. Every IBAN, BIC, EU VAT number and tax ID is checked against its format and check digit, and you get the sheet back with a result and a reason on every row.

No file at hand? (made-up suppliers with documented test numbers).

How to validate a column of IBANs or VAT numbers

  1. Choose the file or paste the list. Excel (.xlsx, .xls), OpenDocument and CSV files work, and so does a column copied from Excel or Google Sheets.
  2. Check the detected columns. Each column is scanned and the ID type is recognised from its values and its header. Change the type if needed, or pick “Mixed” for a column that combines several kinds of ID.
  3. Click Validate. You see how many values are valid, format-only, to check or not valid, and the reason for every problem.
  4. Download the Excel report. It is your sheet with four columns added after each checked column: result, reason, normalised value and detected type, plus a summary sheet.

Private by design: nothing is uploaded

Supplier lists, payroll files and direct-debit mandates combine names with IBANs and tax IDs. That is exactly the data you should not paste into an unknown website. Here the file is opened and checked by JavaScript inside your browser, in a background worker, and never sent anywhere.

You can confirm it in the Network tab of your browser’s developer tools, or load the page, disconnect from the internet and keep validating.

What is checked for each type of ID

Common uses

Why Excel breaks bank and tax IDs

Excel treats anything that looks like a number as a number. A 20-digit account number becomes 1.2341E+19, the last digits are replaced by zeros because Excel keeps only 15 significant digits, and leading zeros disappear from IDs such as 01234567L. A check-digit formula in Excel hits the same wall: you cannot compute mod 97 of a 30-digit IBAN with MOD() without splitting it into pieces. This validator reads the cells as text, warns when Excel already destroyed a value, and does the arithmetic with exact integers.

Known limitations

Frequently asked questions

Is this IBAN and VAT validator really free?

Yes. It is 100% free, with no usage limits, no account and no sign-up. There is no paid plan and no row counter.

Are my files uploaded to a server?

No. The file is read and checked inside your browser, so bank details and tax IDs never leave your device. The page only downloads its own code and an open-source spreadsheet library from this site. If you accept analytics cookies, Google Analytics receives anonymous usage data such as page views, never the contents or names of your files.

Does “valid” mean the VAT number or tax ID is registered?

No. The tool checks the format and the check digit, which catches typos, swapped digits and invented numbers. It cannot tell whether a number was actually issued or is still active. For EU VAT numbers use the European Commission’s VIES service, for Spanish NIFs the AEAT census check, and for other countries the tax agency (SAT, AFIP/ARCA, SII, DIAN, SUNAT).

Which IDs and countries are supported?

IBAN for every country in the SWIFT IBAN registry, BIC/SWIFT codes, EU VAT numbers for all 27 member states plus Northern Ireland (XI), Spanish NIF, DNI, NIE and CIF, the Spanish 20-digit account number (CCC), Mexico RFC and CURP, Argentina CUIT/CUIL, Chile RUT, Colombia NIT and Peru RUC. EU VAT check digits are verified for Spain, Germany, France, Italy, the Netherlands, Belgium, Portugal and Austria; the other member states are checked for format only and marked as such.

Why does an IBAN with correct check digits fail?

Each country has a fixed IBAN length and structure, so a number can pass the mod-97 test and still have the wrong length or letters where digits belong. Spanish IBANs also contain the two control digits of the old account number (CCC); the tool checks those too, which catches errors that the IBAN check digits alone would miss.

Excel shows my IBAN as 1.23E+19 or removed leading zeros. What can I do?

Excel stores long digit strings as numbers and keeps only 15 significant digits, so the rest are lost. The tool flags those cells. Format the column as Text in Excel and type or paste the values again, or export from the source system as CSV and load that file here. A DNI that lost its leading zero (1234567L) is restored and marked as valid.

Is there a limit on the number of rows?

There is no fixed limit and no quota. Validation runs in a background worker and checks around 100,000 values in a second or two on a recent computer; the practical limit is your device’s memory.

Analytics: only if you accept cookies, the page loads Google Analytics (through Google Tag Manager) to count visits and see which tools are used. It never receives the contents or names of your files. You can change your choice at any time with “Cookie settings” at the bottom of the page.