Want to add lump-sum amount in TAX in magento

Question

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?

Thanks.

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.