What Are Bollinger Bands?

Bollinger bands are an integral part of just about every charting system We have ever seen but many traders are unfamiliar with how to use them. The bands are plotted at a standard deviation (statistical term for measuring volatility) around a moving average. Typically the standard deviation used is 2.
A simple moving average in the middle. Most charting software defaults to a 20 period moving average.
An upper band calculated around a simple moving average plus 2 standard deviations.
A lower band calculated around a simple moving average minus 2 standard deviations.
For our examples we will use the most common setting of a 20 period simple moving average. This will give us 3 bands, the middle band of a 20 period simple moving average and the upper and lower bands calculated around the middle band with standard deviation of 2. The closing price is most commonly used to calculate the moving average.
The Squeeze
The squeeze (tightening) is a period of low volatility and often happens before a big move. It can also help identify potential breakout areas

Reversal
In conjunction with other indicators you can identify potential reversal points.

Trending Following
Although Bollinger bands will not tell you when the trend has started if you combine it with certain indicators they will confirm the trend.

Our Use Of Bollinger Bands
As we mentioned earlier Bollinger bands are not really meant to be used as a signal generating indicator but in conjunction with another indictors can be very useful. We like to use Bollinger bands and RSI together to generate possible buy and sell signals or to confirm overbought or oversold areas. When the RSI reads below 30 and price is touching or pushing through the lower band then we know we are oversold and We will either consider buying the market or close existing short positions.

Best Regards
Anand04,