# VAT number format checker: run it free, or from your agent

Checks EU and UK VAT numbers for the right format and check digits, in your browser. No VIES call.

## Prompt

Use looot to check these VAT numbers before I invoice: [paste numbers, one per line]. 1. Set up https://looot.ai/skill.md. 2. Clean each number: upper case, no spaces or dots, GR becomes EL. 3. Check each against its country's format and check digit rule and flag the ones that fail. 4. Return a table of number, country and verdict, and say which ones still need a register check.

## What it needs

VAT numbers with their country prefix

## What comes back

- country of the number
- format valid or not
- check digit result for the countries that have one
- what a valid number looks like for that country

## Endpoints and providers

None. The tool on the web page runs in the browser and calls no endpoint.

## What it costs

Nothing. The tool on the web page runs in the visitor's browser: no account, no API call and no limit per hour. The prompt above runs the same job from your own looot account with current data, billed per call.

## Before you invoice

Catch a typo in a customer's VAT number before it goes on an invoice.

## Clean a customer list

Paste a column of numbers and see which ones fail the format or the check digits.

## Spot the country

See which country a number belongs to from its prefix.

## Check sign-up forms

Use the same rules to stop a mistyped number at the form.

## How do I validate a VAT number?

Paste it with its two letter prefix, such as DE136695976, in the box at the top of this page. You see the country, whether the format is right and whether the check digits match.

## Does this check the EU VIES register?

No. It checks the format and the check digits in your browser. A number can pass here and still not be registered or active. Use the official VIES site of the European Commission to confirm registration.

## Which countries does it cover?

All 27 EU countries plus GB for the United Kingdom and XI for Northern Ireland. Check digits are tested for 20 of them. For the others only the format is checked, and the result says so.

## Why does Greece use EL and not GR?

Greek VAT numbers use the prefix EL. The checker reads GR as EL, so both work.

## What does a check digit failure mean?

The number has the right length and shape, but its last digits do not match the rest. That almost always means a typo. Ask the customer for the number again.

## Can I check many numbers at once?

Yes. Switch to the list mode and paste one number per line. Download the results as CSV.

## Is this VAT number validator free?

Yes. It runs in your browser with no account and no limit. Nothing you type is sent anywhere.

## Related tools

- /free-tools/company-lookup-by-domain
- /free-tools/csv-deduplicator
- /free-tools/phone-number-formatter

## Last reviewed

2026-10-14.