Bollinger Band® Width


The Bollinger Band Width is the difference between the upper and the lower Bollinger Bands divided by the middle band. This technical indicator provides an easy way to visualize consolidation before price movements (low bandwidth values) or periods of higher volatility (high bandwidth values). The Bollinger Band Width uses the same two parameters as the Bollinger Bands: a simple moving- average period (for the middle band) and the number of standard deviations by which the upper and lower bands should be offset from the middle band.

Chart: Bollinger Band Width

How this indicator works

  • During a period of rising price volatility, the distance between the two bands will widen and Bollinger Band Width will increase. Conversely, during a period of low market volatility, the distance between the two bands will contract and Bollinger Band Width will decrease. There is a tendency for bands to alternate between expansion and contraction.
  • When the bands are relatively far apart, that is often a sign that the current trend may be ending. When the distance between the two bands is relatively narrow that is often a sign that a market or security may be about to initiate a pronounced move in either direction.


Band Width = (Upper Bollinger Band - Lower Bollinger Band) / Middle Bollinger Band

Technical analysis focuses on market action — specifically, volume and price. Technical analysis is only one approach to analyzing stocks. When considering which stocks to buy or sell, you should use the approach that you're most comfortable with. As with all your investments, you must make your own determination as to whether an investment in any particular security or securities is right for you based on your investment objectives, risk tolerance, and financial situation. Past performance is no guarantee of future results.