The Money Flow Index (MFI) is an oscillator that uses both price and volume to measure buying and selling pressure. Created by Gene Quong and Avrum Soudack, MFI is also known as volume-weighted RSI. MFI starts with the typical price for each period. Money flow is positive when the typical price rises (buying pressure) and negative when the typical price declines (selling pressure). A ratio of positive and negative money flow is then plugged into an RSI formula to create an oscillator that moves between zero and one hundred. As a momentum oscillator tied to volume, MFI is best suited to identify reversals and price extremes with a variety of signals.
There are several steps involved in the Money Flow Index calculation. The example below is based on a 14-period Money Flow Index, which is the default setting in SharpCharts and the setting recommended by the creators.