---
title: "Definition of BBands"
url: https://signalscreener.fr/definition/bollinger/
markdown_url: https://signalscreener.fr/definition/bollinger.md
description: "Volatility bands placed above and below a moving average, using standard deviation to measure price volatility."
type: glossary-definition
site: Signal Screener
language: en
keywords:
  - "BBands"
  - "Bollinger Bands"
translations:
  de: https://signalscreener.fr/de/definition/bollinger.md
  es: https://signalscreener.fr/es/definition/bollinger.md
  fr: https://signalscreener.fr/fr/definition/bollinger.md
  it: https://signalscreener.fr/it/definition/bollinger.md
  pt: https://signalscreener.fr/pt/definition/bollinger.md
---

# Bollinger Bands

## What is BBands?

Volatility bands placed above and below a moving average, using standard deviation to measure price volatility.

## Think of it like this

Like elastic guardrails on a highway - they widen when the road gets curvy (volatile) and narrow when it's straight (calm).

## Formula

```
Upper = SMA(20) + (2 × StdDev), Lower = SMA(20) - (2 × StdDev)
```

- **Middle Band**: 20-day Simple Moving Average
- **Upper Band**: Middle + 2 standard deviations
- **Lower Band**: Middle - 2 standard deviations
- **Width**: (Upper - Lower) / Middle

## Why it matters

- Shows dynamic support and resistance levels
- Identifies periods of high and low volatility
- Price tends to stay within bands 95% of time
- Squeeze indicates potential breakout

## What's a good value?

| Range | Rating | What it means |
|---|---|---|
| Touch Upper | Overbought | Price at top of range |
| Touch Lower | Oversold | Price at bottom of range |
| Bands Narrowing | Low Volatility | Potential breakout coming |
| Bands Widening | High Volatility | Strong move in progress |

## Real-world example

Price touching the lower band during a squeeze may signal a buying opportunity if trend is bullish.

---

This is educational content, not financial advice.

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