MFI is a momentum indicator, similar to RSI (Relative Strength Index), but it's more rigid because it is volume-weighted, and, therefore, is a good method to measure of the strength of money flowing in and out of a security. As RSI, the MFI scale is 0 - 100 and the indicator is often calculated using a 14 day period.
Formula:
Typical Price is (High + Low + Close) / 3
Positive = Typical * Volume IF Typical > Typical[previous]
Negative = Typical * Volume IF Typical < Typical[previous]
R(N) = Sum(Positive, N) / Sum(Negative, N)
MFI(N) = 100 - (100 / (1 + R(N))
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