The Money Flow Index requires a series of calculations.  First, the period's Typical Price 
is calculated.
 
Next, Money Flow (not the Money Flow Index) is calculated by multiplying the period's 
Typical Price by the volume.
 
If today's Typical Price is greater than yesterday's Typical Price, it is considered 
Positive Money Flow.  If today's price is less, it is considered Negative Money Flow.
Positive Money Flow is the sum of the Positive Money over the specified number of 
periods.  Negative Money Flow is the sum of the Negative Money over the specified number of 
periods.
The Money Ratio is then calculated by dividing the Positive Money Flow by the Negative 
Money Flow.
 
Finally, the Money Flow Index is calculated using the Money Ratio.