Developed by J. Welles Wilder, the Relative Strength Index (RSI) is a momentum oscillator that measures the speed and change of price movements. The classic way to interpret RSI is to look for oversold levels below 30 and overbought levels above 70.

Period: RSI period in bars
offset: 0-100 (optional, defaults to 0)
series: optional, see below


RSI = 100 - ( 100 / (1 + RS))
RS = (average of N up closes) / (average of N down closes)
N = period in bars (typically 14)

RSI is calculated as a series that smooths the impact of large price movements. The RS is calculated using moving averages that are smoothed by previous averages, as explained here: Invest Excel: Relative Strength Index. The more data points that are used to calculate the RSI, the more accurate the results. We use up to 100 bars prior to the first bar (assuming that much exists), which is a compromise between accuracy and performance.


You can use the offset parameter to spot divergence in the RSI and the price action. To screen for RSI(14) > 70, and has increased from the value 10 bars ago, enter:

RSI(14,0) > 70 And RSI(14,0) > RSI(14,10)

You can calculate the benchmark RSI to create a market timing signal. For example to exit all positions when the market is overbought (RSI > 70) enter the following sell rule:

RSI(14,0,#Bench)>70


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