# Validators: IBAN, BSN, VAT, card and ISBN

Check an IBAN, Dutch BSN, credit card number, EU VAT number, email address, URL or ISBN, with the reason when it fails. One value per line.

https://codeknife.dev/en/validators/

## What it does

Checks whether a value is well formed: an IBAN, a Dutch BSN, a card number, an EU VAT number, an email address, a URL or an ISBN. Each is checked the way its own standard defines, and a failure comes with the reason. Paste one value per line to check many at once.

## How to use it

1. Type or paste one value per line. The type of each line is detected on its own, or pick a type under **Check as**.
2. Read the verdict for each value: valid or invalid, the reason when it fails and its parts (country, check digits, domain and so on) when it passes.
3. Copy a single part, or copy the whole list of verdicts.

## Examples

Three values, one per line:

`NL91 ABNA 0417 1643 00` is a valid IBAN, `111222334` fails the BSN check on its check digits, and `978-0-306-40615-7` is a valid ISBN-13 that is also `0306406152` as ISBN-10.

## Good to know

- Valid means well formed with matching check digits. It does not mean an account, card, VAT registration or mailbox exists.
- An IBAN is checked for the length of its country and the mod 97 rule. A BSN of eight digits is read with a leading zero.
- VAT numbers are checked for the format of their country only. Look a business up in VIES to confirm it is registered.
- This tool handles personal data, so it shows no ads and keeps no history or share link of what you enter.

## What does a valid result mean?

It means the value is well formed and its check digits add up, so it could exist. It does not prove that an account is open, a card is active, a VAT number is registered or a mailbox accepts mail: only the issuer can say that.

## Frequently asked questions

### How does the check work for each type?

An IBAN is checked for its country length and the mod 97 rule, a BSN with the eleven-test, a card number with the Luhn algorithm and an ISBN with its check digit. A VAT number is checked against the format of its country, an email address against the usual rules for local part and domain, and a URL for a scheme and a host.

### Is a VAT number checked against the official register?

No. This tool only checks the format of the number for its country. To confirm that a business is registered, look it up in the European Commission VIES service.

### Is what I enter sent anywhere?

No. Every check runs in your browser and the values are not sent to our servers. As this tool handles personal data, it shows no ads and keeps no history of what you enter.