Bollinger Bands


Function Name: boll

Tags: Bands

Category: Trend, Volatility

The Bollinger Bands indicator is one of the most commonly used technical indicators. It draws two bands that are plotted usually two standard deviations above and below a moving average. An upper band is plotted a specified number of standard deviations above this average and a lower band is plotted a specified number of standard deviations below the average.

The Bollinger Bands indicator combines the trend identifying aspects of a moving average with a dynamic factor, each market's own volatility, to plot an envelope. The distance between the bands is, therefore, a reflection of volatility. During sideways periods, prices reaching the bands may indicate overbought or oversold conditions. Strong movement up through the upper band or down through the lower band may indicate the beginning of a trend.


Author:   John Bollinger






Default Value: 20  |  Minimum: 1  |  Maximum: 9999


Type: Numeric



Default Value: 2  |  Minimum: 0  |  Maximum: 5


Type: Numeric



Default Value: -2  |  Minimum: -5  |  Maximum: 0


Type: Numeric