Calculate Markup Percentage is a business term used to define the increase in the amount of money charged for a product or service compared to its cost. Put simply, it is the percentage by which the seller increases the price of a product or service in order to make a profit. In other words, it is the ratio of money earned (income) to money spent (expense). Calculating markup percentage enables businesses to set prices that bring in maximum profits while still appealing to customers and remaining competitive within their markets – making it an essential tool for any successful business!