You have the option to chart up to 3 Exponential Moving Averages (EMAs) at the same time. The 3 input boxes above represent the periods of the Exponential Moving Averages you wish to chart. If you are charting on minute, daily or weekly periods, the EMA periods you indicate above will be for minutes, days and weeks, respectively. An EMA differs slightly from a Simple Moving Average (SMA) in that it gives extra weight to more recent price data. This allows investors to track and respond quickly to recent price trends that might take more time to appear in an SMA. The formula for an EMA is: EMA = price today * K + EMA yest * (1-K) where K = 2 / (N+1). Like an SMA, it smooths out a data series, making it easier to spot trends.