Money Flow Index (MFI) is the technical indicator, which indicates the rate at which money is invested into a security and then withdrawn from it. Construction and interpretation of the indicator is similar to Relative Strength Index with the only difference that volume is important to MFI.
When analyzing the money flow index one needs to take into consideration the following points:
The calculation of Money Flow Index includes several stages. At first one defines the typical price (TP) of the period in question:
TP = (HIGH + LOW + CLOSE) / 3
Then one calculates the amount of the Money Flow (MF):
MF = TP * VOLUME
If todays typical price is larger than yesterdays TP, then the money flow is considered positive. If todays typical price is lower than that of yesterday, the money flow is considered negative.
POSITIVE MONEY FLOW is a sum of positive money flows for a selected period of time. NEGATIVE MONEY FLOW is the sum of negative money flows for a selected period of time.
Then one calculates the money ratio (MR) by dividing the positive money flow by the negative money flow:
MR = POSITIVE MONEY FLOW / NEGATIVE MONEY FLOW
And finally, one calculates the money flow index using the money ratio:
MFI = 100 - (100 / (1 + MR)
HIGH the high price of the current bar;
LOW the low price of the current bar;
CLOSE the close price of the current bar;
VOLUME the volume of the current bar.