Cash flow income is a form of income generated by the cash that is coming in to a business minus any cash that is going out. It’s also known as liquid income and is typically used to measure financial performance as cash can be more easily monitored than other forms of income. When looking at cash flow income, it’s important to consider all sources – from sales, to investments and other forms of revenue. Put simply, your cash flow income is the money you make minus the money you spend.