Profitability index (PI) is like a score to measure how much money a company can make with a project. To get the score, you need to add up all of the future cash flows (money you expect to receive in the future) the project will bring and then divide that number by the amount of money it will cost to complete the project. It's kind of like a short cut to decide if a project is worth doing. The higher the score the more money you will make – the better the project!