# Document dates

Source: https://developer.avalara.com/vat-erp/transactions/simple-transactions/document-dates/

The `date` field indicates the calendar day on which a transaction occurred. Note that AvaTax calculations based on the calendar day without taking into account the timezone. Whatever the calendar day is locally when you create the transaction, AvaTax calculates tax based on the tax laws in effect on that calendar day.

AvaTax requires this field because the date determines the tax rules for a transaction and because systems can misinterpret calendar days when a transaction occurs close to a time zone boundary.

**Note:**  

If you want to use a different date to calculate tax rates, you can specify a `taxOverride` with a type of `taxDate`.