Studies · Bands and channels
Bollinger %B
bollingerPercentB · Bollinger %B — where price sits inside its own channel
Drawn in its own panelReads one column (close here)Guide lines at 0, 1
Hover the chart to read values · practice data: a seeded random walk with no overnight gaps
What it measures
Where the price sits inside its Bollinger Bands, as a fraction: 1 is on the upper band, 0 on the lower band, 0.5 on the middle. Above 1 or below 0 means price is outside the bands.
How traders use it
- Overbought and oversold in a range: readings above 1 or below 0 are candidates to fade.
- Trend strength: in a strong trend %B stays above 0.5 (uptrend) or below it (downtrend) for long stretches.
- Divergence: a new price high with a lower %B means the push is weaker relative to volatility.
- Because it is normalized, it can be used inside trading rules and compared between instruments.
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. |