I am having trouble with the Magento shopping cart.

I want the final price to be calculated by the product weight. I have entered the weight in product details and the price but still in the shopping cart i get the Subtotal without a weight calculation. How can I fix this.

Currently the shopping cart qty unit is multiplied by price to give mt the price. Instead I want when qty = 1 WEIGHT X PRICE

  • If you have fixed the weight of your product, then you should be able to fix the price to price per unit = weight*price
    – eetzen
    Commented Dec 20, 2014 at 3:20

2 Answers 2


Magento doesn't support price calculation the way you describe in your question. You should probably configure your products like this.

For example: ProductX costs 10 euro per kilo.

In that case you have:

  • price: 10.00
  • weight: 1

If customers want to purchase 2 kilo of ProductX, they buy a quantity of 2 of ProductX. Which will cost 20 euro. (ProductX x 2 = 20)

If you need customers to be able to buy 2.5 kilo of ProductX, you can allow this in the product settings.

In the tab Inventory, you will find the option Qty Uses Decimals. If you set this to Yes, customers will be able to purchase 2.5 x ProductX.


Which shipping method are you using? In the Table Rates shipping method the default Condition is Weight vs Destination which allows you excactly do what you want. Just download the table rates CSV after switching the current configuration scope, change the shipping rates as per your requirement and then re-upload your CSV.

Magento Shipping Methods

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