Here is what you have to do to enable display of the tax on shopping cart page of the Magento.
In your admin go to System > Configuration > Shipping Settings, and then fill out all the details under Origin. Make sure you have added the proper country and also you have to make sure that you have added or edited the TAX rules with percentage from
ADMIN >> SALES >> MANAGE TAX.
And don’t forget to clean your cache,
Done, go to Magento Shopping Cart and you will see appropriate tax there.