i want to apply custom discount on grand total (without coupons) in create order section in magento admin.

i have added 2 lines code for check in this file app\code\core\Mage\Adminhtml\Block\Sales\Order\Create\Items\Grid.php

in function

public function getSubtotal()

        if ($this->displayTotalsIncludeTax()) {
            if ($address->getSubtotalInclTax()) {

                return $address->getSubtotalInclTax();


            return $address->getSubtotal()+$address->getTaxAmount();
        } else {
     $address->setDiscountDescription('Custom Discount');

     return $address->getSubtotal();
        return false;

but it is not only applied on subtotal of products not on grand total

see here output of applied code

Need help to find correct function.

  • what did u try? Jun 12, 2015 at 10:23
  • @Manashvibirla just added two lines $address->setDiscountAmount(-(400)); $address->setDiscountDescription('Custom Discount'); to check it. but it this $400 discount applied on subtotal only not on grand total . i think there is any other function to calculate grand total .
    – Ashvini K
    Jun 12, 2015 at 10:29
  • @AshviniMarwal Suppose if i want to enter discount price at order page how can i change.. Now your code looks like assigned discount order amount in code. i need change randomly so assigning discount amount in code is not a good idea.
    – zus
    Feb 5, 2018 at 5:41

1 Answer 1


I have fixed. issue was in get price with tax.

  • can you please add your code here i m also stuck with problem like you.Thanks
    – Zahirabbas
    Mar 25, 2016 at 7:35
  • follow this article excellencemagentoblog.com/blog/2012/01/27/…
    – Ashvini K
    May 16, 2016 at 7:07
  • @Zaheerabbas Could you pls explain how you achieve this.
    – zus
    Feb 5, 2018 at 5:47
  • @Zaheerabbas what issue you are facing ?
    – Ashvini K
    Feb 5, 2018 at 8:26

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