BandWidth

BandWidth is the definitive clean build of John Bollinger's BandWidth measure: the gap between upper and lower band as a fraction of the basis, plotted with a gradient fill above zero. Two reference lines track the lowest and highest readings of a configurable lookback (the Squeeze Level and Bulge Level), so the current width is always judged against its own recent extremes instead of an absolute level.

How to Trade the BandWidth?

• BandWidth at the Squeeze Level: volatility is unusually compressed (a condition, not a direction) and the environment where directional moves are often born.
• Expansion off the low: the Expansion From Squeeze Low alert fires when width turns up from its lookback low, the moment compression starts resolving.
• BandWidth at the Bulge Level: width this stretched is rarely sustained and frequently appears near trend endings, a prompt to protect profits rather than initiate.
• Direction comes from price: pair the width read with price structure or a breakout tool; the metric itself is deliberately non-directional.

BandWidth Settings

• Length (default 20): bars for the simple moving average basis and the standard deviation.
• Source (default close): price series the bands are computed from.
• Multiplier (default 2): standard deviation multiple, so the default bands sit four standard deviations apart.
• Reference Lookback (default 125): window locating the Squeeze and Bulge references, roughly six months of daily bars.
• Show Squeeze Level / Show Bulge Level (default on): plot the lookback low and high of BandWidth.
• Extreme Markers (default off): circles where BandWidth tags either reference; the alerts work regardless.
• Gradient Fill (default on): shades the area between zero and the BandWidth line.

Frequently Asked Questions

What is the difference between BandWidth and %B?

Why is the Reference Lookback 125 bars?

Can the Squeeze persist without a breakout?