 Type: momentum oscillator
 Data requirement: daily closes for individual stock
 Inputs
 no. of periods (n) to use (suggested default is 14)
 previous average gain
 previous average loss
 current gain
 current loss
 Formulas
 Gain = close(k) – close(k1), when close(k) is higher than close(k1), where k is the trading day for calculation
 Loss = close(k1) – close(k), when close(k) is lower than close(k1), where k is the trading day for calculation
 Initial
 First Average Gain = Sum of Gains over the past n periods / n
 First Average Loss = Sum of Losses over the past n periods / n
 Subsequent

Average Gain = [(Previous Average Gain) x (n1) + Current Gain] / n
 Average Loss = [(Previous Average Loss) x (n1) + Current Gain] / n

 RS = Average Gain / Average Loss
 RSI = 100 – 100 / (1 + RS)
 Signals
 Oversold: below 30
 Overbought: above 70
 Divergences
 Failure swings
 Centerline crossovers
 General trend
 c.f. http://stockcharts.com/school/doku.php?id=chart_school:technical_indicators:relative_strength_in
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