It's quite common for a person who has anything to do with sales to have to calculate profit margin and VAT at the same time. As with most calculators at Omni, you are free to pick which value is going to be calculated. The order of fields is based on the most common scenario, but I can easily imagine a situation where you'd like to come up with a max price you're willing to pay (I need to sell it for
$140 and maintain my usual
40% margin). We have a margin and sales tax alternative for those of you operating in countries when sales tax is used instead of VAT.