Studies · Bands and channels
Bollinger BandWidth
bollingerBandwidth · Bollinger BandWidth — the channel's width in percent of price
Drawn in its own panelReads one column (close here)
Hover the chart to read values · practice data: a seeded random walk with no overnight gaps
What it measures
How wide the Bollinger Bands are, as a percentage of the middle band: 100 × (upper − lower) ÷ middle. It turns the visual pinch and flare of the bands into a number.
How traders use it
- The squeeze: BandWidth at its lowest level in months means volatility has compressed, which often comes before a sharp move. Traders then wait for price to break out of the bands to pick a direction.
- Very high BandWidth after a big move often marks the end of that move, as volatility peaks.
Parameters
| Name | Value | Default | Allowed | What it does |
|---|---|---|---|---|
| period | 20 | ≥ 1 usual 10–50 | Bars in the underlying Bollinger moving average and standard deviation. | |
| stdDev | 2 | any usual 1–3 | Band distance in standard deviations, as in Bollinger Bands. |