RSI or Relative Strength Index is an oscillator that uses the change from one closing price to the next to tell you when a pair is oversold or overbought. Default ranges between 0 and 100, with a value less than 30 generally meaning “highly oversold” and more than 70 meaning “highly overbought”, though some traders use 20 and 80.
Like most oscillators the RSI is most-valuable in range-bound markets and least-valuable in trending markets.



