For countries such as UK and Australia where store owners are entering prices inclusive of sales tax (VAT, GST) we now have {tag_producttaxpercentage,percentage} and  {tag_totaltaxpercentage,percentage} to use on the shopping cart and invoice layouts which will calculate and display tax based on the retail or sale price entered for the product.

To use this tag, you should enter in the prices of all your products inclusive of tax. That way when the products are displayed on your online store their prices will be the final prices that your customers will be paying. To show how much of their product price will be paid as a sales tax in the shopping cart layout simply replace the standard {tag_producttaxamount} tag with a {tag_producttaxpercentag, 12.5} tag where 12.5 is the percentage of tax to be paid.