***
title: "TaxZoneStrategy"
generated: true
---------------
Defines how the active [Zone](/current/core/reference/typescript-api/entities/zone#zone) is determined for the purposes of calculating taxes.
This strategy is used in 2 scenarios:
1. To determine the applicable Zone when calculating the taxRate to apply when displaying ProductVariants. In this case the
`order` argument will be undefined, as the request is not related to a specific Order.
2. To determine the applicable Zone when calculating the taxRate on the contents of a specific Order. In this case the
`order` argument *will* be defined, and can be used in the logic. For example, the shipping address can be taken into account.
Note that this method is called very often in a typical user session, so any work it performs should be designed with as little
performance impact as possible.
:::info
This is configured via the `taxOptions.taxZoneStrategy` property of
your VendureConfig.
:::
```ts title="Signature"
interface TaxZoneStrategy extends InjectableStrategy {
determineTaxZone(
ctx: RequestContext,
zones: Zone[],
channel: Channel,
order?: Order,
): Zone | Promise | undefined;
}
```
* Extends: [`InjectableStrategy`](/current/core/reference/typescript-api/common/injectable-strategy#injectablestrategy)
### determineTaxZone
\
RequestContext, zones: Zone[], channel: Channel, order?: Order) => Zone | Promise<Zone> | undefined`} />