# Technical Studies Reference

### Bollinger Bands: Bandwidth

This study calculates and displays the Bandwidth of a pair of Bollinger Bands for the data specified by the Input Data Input. The Bandwidth is expressed relative to a Simple Moving Average of the Input Data. Refer to the documentation of those studies for an explanation of the notation used here. We denote the Bollinger Bands: Bandwidth at Index $$t$$ as $$BW_t(X,n,v)$$, and we compute it for $$t \geq n - 1$$ as follows.

$$BW_t(X,n,v) = \displaystyle{\frac{TB^{(B)}_t(X,n,v) - BB^{(B)}_t(X,n,v)}{SMA_t(X,n)}}$$

Note: Depending on the setting of the Input Moving Average Type, the Simple Moving Average the above formula could be replaced with an Exponential Moving Average, a Linear Regression Moving Average, a Weighted Moving Average, a Wilders Moving Average, a Simple Moving Average - Skip Zeros, or a Smoothed Moving Average.