# Tax calculation date

Source: https://developer.avalara.com/avatax-dm-combined-erp/sales-tax-badge/transactions/cert-tax-calc-date/

# Tax calculation date

**Element type: Required**

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

Your solution must allow users to optionally specify a date other than the document`date` for calculating tax on the transaction. This value will override the date field on the transaction.

This can be done by allowing users to specify a [taxOverride](https://developer.avalara.com/api-reference/avatax/rest/v2/models/TaxOverrideModel/) value of`taxDate` at either the document level or the line level.

```
{    "lines": [        {            "number": "1",            "quantity": 1,            "amount": 100,            "taxCode": "PS081282",            "itemCode": "Y0001",            "description": "Yarn"        }    ],    "addresses": {        "singleLocation": {            "line1": "2000 Main Street",            "city": "Irvine",            "region": "CA",            "country": "US",            "postalCode": "92614"        }    },    "taxOverride": {      "type": "TaxAmount",      "taxAmount": 6.25,      "taxDate": "2020-10-16",      "reason": "Precalculated Tax"    },    "type": "SalesInvoice",    "companyCode": "DEFAULT",    "date": "2020-10-20",    "code": "XYZ",    "customerCode": "ABC",    "purchaseOrderNo": "123456789",    "commit": true,    "currencyCode": "USD",    "description": "Yarn"}
```

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