VOLATILITY, DISPERSION & CANDLES
Bollinger Bands
A 20-day average with bands 2 standard deviations out — a map of "normal" vs "stretched".
spec id: bollingeroutputs: upper · mid · lower · width · pctlength (default 20) · std (default 2)
What does Bollinger measure?
A price channel that hugs the stock. Touching the top band means unusually expensive versus its own recent self; the bottom band, unusually cheap.
How is Bollinger calculated?
Draw the 20-candle average closing price for the middle line. Then measure how jumpy those 20 closes were around that average, and draw the bands 2 of those jumps above and below. Calm stock, tight bands; wild stock, wide bands. `width` is the gap between them and `pct` is where today's price sits inside it (0 at the bottom band, 1 at the top).
Written by reading the engine’s real computation, not a textbook — where the two differ, the page describes what actually runs.
How do traders read Bollinger?
Touching the lower band = stretched down; bands pinching tight (a squeeze) often precede a bigger move.
The honest caveat
A band touch alone is not an edge — price can ride a band for weeks in a trend. Pair it with a regime check.
How do I use Bollinger in a bot?
Add indicator → Bollinger. Outputs: upper, mid, lower.
Related indicators
- Chaikin volatilityHow fast the market's daily range is expanding or shrinking, in percent.
- Chandelier exitA trailing stop that hangs from the recent extreme, a set distance away.
- Close location valueWhere the close landed inside the candle.
- Coeff of variationVolatility measured relative to price level, so a $10 stock and a $500 stock can be compared fairly.
Or browse all 158 indicators in the full library.