I want to add some amount in TAX in magento. How this can be done?

Like in cart when we calculate shipping & handling at that time, shipping & handling comes but below that....TAX coming. I want to know the location from where the Tax is returned....something like this - return $tax; so that I can add an amount there & that will be used in whole site. I do not want a phtml file. I want a core file from which the tax is returned & I can add some amount & that will be used in whole site.

I checked the files inside Tax module built-in coming in magento but very hard to determine from where the final tax is returned :(

Another thing is I searched for it & got some solutions like add custom modules & through it add the custom fee but I do not want a separate module for it.

Any Help Please?


1 Answer 1


You can find that on tax/calculation model.

Go to app/code/core/Mage/Tax/Model/Calculation.php there you can find a function named calcTaxAmount() there you can see that the function is returning a variable name $amount. That is the tax amount which is being applied.

Hope this help you to find your answer.

  • Thank you Ashish for your quick reply :) I am giving it a try & getting back to you. Thanks again Ashish :)
    – KA9
    Commented Apr 22, 2016 at 6:22
  • You made a spelling mistake on my name that will be Asish not Ashish :D :D
    – Asish Hira
    Commented Apr 22, 2016 at 6:23
  • Let me know what happen
    – Asish Hira
    Commented Apr 22, 2016 at 6:34
  • Hi Asish, yes you are right...sorry for the spelling mistake :) haha Yes so now the situation is that.....we have some issues in server & it is not working right now....as soon as it starts working again....I will definitely get back to you :) Thanks again Asish for helping here quickly :)
    – KA9
    Commented Apr 22, 2016 at 6:44
  • 1
    Yes ok Asish, ok so I am continuing on this one & will post if I got any fruitful thing but you have provided the exact file and method here so that is enough for me to go ahead :) Thank Asish for your great help :)
    – KA9
    Commented Apr 22, 2016 at 7:48

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