# Include tax in line amounts

Source: https://developer.avalara.com/vat-erp/transactions/certification-requirements/include-tax-in-line-amounts/

**Element type:** Required

**Endpoints/models used:** [LineItemModel](https://developer.avalara.com/api-reference/avatax/rest/v2/models/LineItemModel/)

Your implementation must allow users to specify whether the total amount of a line item includes tax. You can accomplish this using the `isTaxIncluded` field at the line level. This flag tells AvaTax to use a product’s price as a target for the total sale. As a result, AvaTax will back the tax out of the total amount provided in the request. Consider the following scenarios:

-   **Tax Excluded Scenario**: When you sell a product for a price of €100, tax gets calculated on the amount and added to the total sale price. The local VAT rate in France is 20%, so with tax you’ll pay €120, and the merchant selling you the product will pay €20 to the tax authority on their VAT return. The result is that you get your product, the merchant gets €100, and the tax authority gets €20.

-   **Tax Included Scenario**: Now, let’s introduce the `isTaxIncluded` option. When you set `isTaxIncluded` to true, AvaTax will perform slightly different math. Instead of calculating the tax on top of the purchase amount, AvaTax calculates tax to ensure that the final amount equals €100. The result is that you still calculate the correct tax rate, but the merchant knows the revenue amount when the sale is made, with no month-end finagling. The merchant keeps €83.33 and pays €16.67 in tax - which reflects the correct tax rate of 20%.

The `isTaxIncluded` parameter appears in the [LineItemModel](https://developer.avalara.com/api-reference/avatax/rest/v2/models/LineItemModel/). This allows you to sell a mixture of tax-included and tax-excluded lines in a single transaction.

[![Closed](https://avalara-devdocs-prod.mcoutput.com/vat-erp/Skins/Default/Stylesheets/Images/transparent.gif)View example](javascript:void\(0\);)

```
 {  "lines": [    {      "number": "1",      "quantity": 1,      "amount": 100,      "taxCode": "PS081282",      "itemCode": "Y0001",      "description": "Yarn",      "isTaxIncluded": true    }  ],  ...} 
```