# Rule condition: Invalid GTIN or EAN

### Use cases

* Detect and exclude items with invalid GTINs or EANs (for some channels, such as Amazon, GTINs or EANs are mandatory)

### is valid

Use the **is valid** action to check that GTIN or EAN values are valid. The correct GTIN format is eight, twelve, thirteen or fourteen digits.

### is not valid

Use the **is not valid** action to check if the GTIN or EAN format is correct. This action [calculates a check digit](https://www.gs1.org/services/check-digit-calculator) (which makes sure the barcode is put together correctly).

<figure><img src="/files/8f96fbb61fbc49c291ce2b7696b43f4a7a206e53" alt=""><figcaption></figcaption></figure>

{% hint style="info" %}
In **Setup > Edit mapping**, make sure the field is mapped correctly and is the correct type, as these actions can only be used for GTIN and EAN fields.
{% endhint %}

<figure><img src="/files/833e943d619e9619806806395cbfa3be8525af67" alt=""><figcaption></figcaption></figure>


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