I want to add to sales rules for cart a rule where to add subtotal with TAX because I cannot relay on subtotal without TAX as I have products with different TAX class and different VAT values.

For example I have a product with VAT 19% and a product with VAT 9%, the I cannot trust the subtotal without TAX value, as it will depend on what type of products I add to the cart, in order for the rule to work correctly.

I want to apply a rule for subtotal bigger than 200 but I need to have subtotal with TAX.

How can I do this?

1 Answer 1


You could try something like this as a rewrite. I'm assuming you already know how to write a custom module.



Rewrite class

class Vendor_Module_Model_SalesRule_Rule_Condition_Address extends Mage_SalesRule_Model_Rule_Condition_Address
    public function loadAttributeOptions()



        $attributes = $this->getAttributeOption();

        $attributes['base_subtotal_with_tax'] = Mage::helper('salesrule')->__('Subtotal after tax');


        return $this;


     * (non-PHPdoc)
     * @see Mage_SalesRule_Model_Rule_Condition_Address::getInputType()

    public function getInputType()


        if ($this->getAttribute() == 'base_subtotal_with_tax')

            return 'numeric';

        return parent::getInputType();


     * Add field "base_subtotal_with_tax" to address.
     * It is need to validate the "base_subtotal_with_tax" attribute
     * @see Mage_SalesRule_Model_Rule_Condition_Address::validate()

    public function validate(Varien_Object $address)


        $subAfterDiscount = // code to calculate subtotal with tax

        $address->setData('base_subtotal_with_tax', $subAfterDiscount);

        return parent::validate($address);


  • Thank you! It is working in checkout but is not applying the rule in shopping cart page. It is working only in one page checkout!
    – andy1786
    Apr 26, 2020 at 20:24
  • I'm not sure why that is. Maybe because in shopping cart, the address is not set yet for the customer? I haven't tested it that much to be honest. I mean it's validating the rule based on address as I'm rewriting the Rule_Condition_Address.
    – gabtzi
    Apr 27, 2020 at 7:17

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