---
title: Shipping calculator
slug: commerce-connect-15/docs/shipping-calculator
docTags: 
createdAt: 2026-07-30T20:34:41.000Z
---

## shippingCost

Calculates the shipment's shipping cost.

```csharp
public void GetShippingCost(IShipment shipment, IMarket market, Currency currency, IShippingCalculator shippingCalculator) {
  var shippingCost = shippingCalculator.GetShippingCost(shipment, market, currency);
  Debug.WriteLine("Shipping cost for shipment '{0}': {1}", shipment.ShipmentId, shippingCost);
}
```

## shippingDiscountedAmount

Calculates the shipping cost after applying the shipping discount.

```csharp
public void GetDiscountedShippingAmount(IShipment shipment, IMarket market, Currency currency, IShippingCalculator shippingCalculator) {
  var shippingDiscountedAmount = shippingCalculator.GetDiscountedShippingAmount(shipment, market, currency);
  Debug.WriteLine("Shipping discounted amount for shipment '{0}': {1}", shipment.ShipmentId, shippingDiscountedAmount);
}
```

## shipmentSubtotal

Calculates the subtotal for all line items in the shipment, which is the sum of the discounted prices of all non-gift line items in the shipment.

```csharp
public void GetShippingItemsTotal(IShipment shipment, Currency currency, IShippingCalculator shippingCalculator) {
  var shipmentSubtotal = shippingCalculator.GetShippingItemsTotal(shipment, currency);
  Debug.WriteLine("Subtotal for shipment '{0}': {1}", shipment.ShipmentId, shipmentSubtotal);
}
```

## shippingItemTotal

Calculates the subtotal for all return line items in the shipment, which is the sum of the discounted prices of all non-gift return line items in the shipment.

```csharp
public void GetShippingReturnItemsTotal(IShipment shipment, Currency currency, IShippingCalculator shippingCalculator) {
  var shippingItemTotal = shippingCalculator.GetShippingReturnItemsTotal(shipment, currency);
  Debug.WriteLine("Total prices of all return line items for shipment '{0}': {1}", shipment.ShipmentId, shippingItemTotal);
}
```

## shippingTax

Calculates a shipment's shipping tax.

```csharp
public void GetShippingTax(IShipment shipment, IMarket market, Currency currency, IShippingCalculator shippingCalculator) {
  var shippingTax = shippingCalculator.GetShippingTax(shipment, market, currency);
  Debug.WriteLine("Shipping tax for shipment '{0}': {1}", shipment.ShipmentId, shippingTax);
}
```

## salesTax

Calculates a shipment's sales tax based on the shipping address.

```csharp
public void GetSalesTax(IShipment shipment, IMarket market, Currency currency, IShippingCalculator shippingCalculator) {
  var salesTax = shippingCalculator.GetSalesTax(shipment, market, currency);
  Debug.WriteLine("Sales tax for shipment '{0}': {1}", shipment.ShipmentId, salesTax);
}
```

## returnShippingTax

Calculates a shipment's return shipping tax.

```csharp
public void GetReturnShippingTax(IShipment shipment, IMarket market, Currency currency, IShippingCalculator shippingCalculator) {
  var returnShippingTax = shippingCalculator.GetReturnShippingTax(shipment, market, currency);
  Debug.WriteLine("Shipping tax for return shipment '{0}': {1}", shipment.ShipmentId, returnShippingTax);
}
```

## returnSalesTax

Calculates the sales tax for a return shipment that contains return line items.

```csharp
public void GetReturnSalesTax(IShipment shipment, IMarket market, Currency currency, ISalesTaxCalculator salesTaxCalculator) {
  var returnSalesTax = salesTaxCalculator.GetReturnSalesTax(shipment, market, currency);
  Debug.WriteLine("Sales tax for return shipment '{0}': {1}", shipment.ShipmentId, returnSalesTax);
}
```

## shippingTotals

Calculates all shipping totals for the shipment (subtotal, shipping cost, and shipping tax).

```csharp
public void GetShippingTotals(IShipment shipment, IMarket market, Currency currency, IShippingCalculator shippingCalculator) {
  var shippingTotals = shippingCalculator.GetShippingTotals(shipment, market, currency);
  Debug.WriteLine("Subtotal for shipment '{0}': {1}", shipment.ShipmentId, shippingTotals.ItemsTotal);
  Debug.WriteLine("Shipping cost for shipment '{0}': {1}", shipment.ShipmentId, shippingTotals.ShippingCost);
  Debug.WriteLine("Shipping tax for shipment '{0}': {1}", shipment.ShipmentId, shippingTotals.ShippingTax);
}
```

## Change the default calculation

Inherit from `DefaultShippingCalculator`, the default implementation of `IShippingCalculator`, and override one or more of its methods to change the calculation behavior. For example:

- To change the shipping cost calculation, override one or more of the `CalculateShippingCost` overloads.
- To change the shipping items total, override `CalculateShippingItemsTotal`.
- To change tax calculations, override the corresponding `CalculateShippingTax`, `CalculateReturnShippingTax`, or `CalculateSalesTax` method.

```csharp
public class ShippingCalculatorOverridingDefault: DefaultShippingCalculator {
  public ShippingCalculatorOverridingDefault(ILineItemCalculator lineItemCalculator,
    IReturnLineItemCalculator returnLineItemCalculator,
    ITaxCalculator taxCalculator): base(lineItemCalculator, returnLineItemCalculator, taxCalculator) {}
  protected override ShippingMethodDto GetShippingMethods() {
    return new ShippingMethodDto();
  }
  protected override Money CalculateShippingCost(IShipment shipment, IMarket market, Currency currency) {
    return new Money(0m, currency);
  }
  protected override bool CanBeConverted(Money moneyFrom, Currency currencyTo) {
    return true;
  }
  protected override Money CalculateShippingItemsTotal(IShipment shipment, Currency currency) {
    return new Money(0, currency);
  }
  protected override Money CalculateShippingReturnItemsTotal(IShipment shipment, Currency currency) {
    return new Money(0, currency);
  }
  protected override Money CalculateShippingTax(IShipment shipment, IMarket market, Currency currency) {
    return new Money(0, currency);
  }
  protected override Money CalculateReturnShippingTax(IShipment shipment, IMarket market, Currency currency) {
    return new Money(0, currency);
  }
}
```

## Change the default validation

The default implementation validates that each return value is non-negative after calculation. To change the behavior, override the appropriate method: `ValidateShippingCostForShipment`, `ValidateShippingItemTotal`, `ValidateShippingTax`, or `ValidateSalesTax`.

```csharp
public class ShippingCalculatorOverridingDefault: DefaultShippingCalculator {
  public ShippingCalculatorOverridingDefault(
    ILineItemCalculator lineItemCalculator,
    IReturnLineItemCalculator returnLineItemCalculator,
    ITaxCalculator taxCalculator): base(lineItemCalculator, returnLineItemCalculator, taxCalculator) {}

  protected override void ValidateShippingCostForShipment(Money money) {
    if (money.Amount < 0) {
      throw new ValidationException("Shipping cost must not be negative.");
    }
  }

  protected override void ValidateShippingItemTotal(Money money) {
    if (money.Amount < 0) {
      throw new ValidationException("Shipping item total must not be negative.");
    }
  }

  protected override void ValidateShippingTax(Money money) {
    if (money.Amount < 0) {
      throw new ValidationException("Shipping tax must not be negative.");
    }
  }

  protected override void ValidateSalesTax(Money money) {
    if (money.Amount < 0) {
      throw new ValidationException("Sales tax must not be negative.");
    }
  }
}
```