The Money Flow indicator illustrates the inflows and outflows of cash in regards to a particular stock. While a stock's price simply provides a snapshot in time, Money Flow can show if the market may be discounting some future, significant event.
The equation for Money Flow calculation is simply:
Money Flow = (Typical Price) * (Volume)
Where Typical Price is defined as: (High + Low + Close) / 3
Money Flow values can be used as an independent measurement or as part of the Money Flow Index equation.