*** title: "OrderTaxCalculationStrategy" generated: true --------------- ## OrderTaxCalculationStrategy Defines how order-level tax totals and the tax summary are calculated. The default implementation ([DefaultOrderTaxCalculationStrategy](/current/core/reference/typescript-api/tax/order-tax-calculation-strategy#defaultordertaxcalculationstrategy)) rounds tax at the individual line level and then sums. This is the standard Vendure behaviour. An alternative implementation ([OrderLevelTaxCalculationStrategy](/current/core/reference/typescript-api/tax/order-tax-calculation-strategy#orderleveltaxcalculationstrategy)) groups net subtotals by tax rate and rounds once per group, which eliminates per-line rounding accumulation errors. This approach is required by certain jurisdictions and ERP systems. :::info This is configured via the `taxOptions.orderTaxCalculationStrategy` property of your VendureConfig. ::: ```ts title="Signature" interface OrderTaxCalculationStrategy extends InjectableStrategy { calculateOrderTotals(order: Order): OrderTotalsResult; calculateTaxSummary(order: Order): OrderTaxSummary[]; } ``` * Extends: [`InjectableStrategy`](/current/core/reference/typescript-api/common/injectable-strategy#injectablestrategy)

### calculateOrderTotals \Order) => OrderTotalsResult`} /> Calculates the order totals (subTotal, subTotalWithTax, shipping, shippingWithTax) for the given Order. This is called frequently during promotion application, so it should be as cheap as possible - avoid building tax summary data here. The Order's `lines` and `surcharges` relations must be loaded. `shippingLines` may be empty/unloaded, in which case shipping is treated as zero. ### calculateTaxSummary \Order) => OrderTaxSummary[]`} /> Calculates the full tax summary for the given Order. This is called once when the `taxSummary` getter is accessed on the Order entity. This method must be synchronous, as it is called from the `taxSummary` getter on the Order entity. The Order's `lines`, `surcharges`, and `shippingLines` relations must be loaded.

## DefaultOrderTaxCalculationStrategy The default [OrderTaxCalculationStrategy](/current/core/reference/typescript-api/tax/order-tax-calculation-strategy#ordertaxcalculationstrategy). Tax is rounded at the individual line level and then summed. This matches the standard Vendure behaviour prior to the introduction of this strategy. ```ts title="Signature" class DefaultOrderTaxCalculationStrategy implements OrderTaxCalculationStrategy { calculateOrderTotals(order: Order) => OrderTotalsResult; calculateTaxSummary(order: Order) => OrderTaxSummary[]; } ``` * Implements: [`OrderTaxCalculationStrategy`](/current/core/reference/typescript-api/tax/order-tax-calculation-strategy#ordertaxcalculationstrategy)

### calculateOrderTotals \Order) => OrderTotalsResult`} /> ### calculateTaxSummary \Order) => OrderTaxSummary[]`} />

## OrderLevelTaxCalculationStrategy An [OrderTaxCalculationStrategy](/current/core/reference/typescript-api/tax/order-tax-calculation-strategy#ordertaxcalculationstrategy) that groups net subtotals by tax rate and rounds once per group. This eliminates per-line rounding accumulation errors present in the [DefaultOrderTaxCalculationStrategy](/current/core/reference/typescript-api/tax/order-tax-calculation-strategy#defaultordertaxcalculationstrategy). This approach is required by certain jurisdictions and ERP systems that expect tax to be calculated on the subtotal per tax rate rather than per line. Note that when using this strategy, the `taxTotal` in the tax summary may differ by ±1 minor unit from the sum of individual line-level `proratedLineTax` values. This is expected and is the intended behaviour. *Example* ```ts import { OrderLevelTaxCalculationStrategy, VendureConfig } from '@vendure/core'; export const config: VendureConfig = { taxOptions: { orderTaxCalculationStrategy: new OrderLevelTaxCalculationStrategy(), }, }; ``` ```ts title="Signature" class OrderLevelTaxCalculationStrategy implements OrderTaxCalculationStrategy { calculateOrderTotals(order: Order) => OrderTotalsResult; calculateTaxSummary(order: Order) => OrderTaxSummary[]; } ``` * Implements: [`OrderTaxCalculationStrategy`](/current/core/reference/typescript-api/tax/order-tax-calculation-strategy#ordertaxcalculationstrategy)

### calculateOrderTotals \Order) => OrderTotalsResult`} /> ### calculateTaxSummary \Order) => OrderTaxSummary[]`} />

## OrderTotalsResult The result of an [OrderTaxCalculationStrategy](/current/core/reference/typescript-api/tax/order-tax-calculation-strategy#ordertaxcalculationstrategy)'s `calculateOrderTotals` method. ```ts title="Signature" interface OrderTotalsResult { subTotal: number; subTotalWithTax: number; shipping: number; shippingWithTax: number; } ```

### subTotal \ ### subTotalWithTax \ ### shipping \ ### shippingWithTax \