What Are Bollinger Bands?
Bollinger Bands are a volatility indicator invented by trader John Bollinger in the 1980s. They consist of three lines drawn directly on the price chart: a middle moving average with one upper band and one lower band on either side. The gap between the bands expands when the market is volatile and contracts when it's quiet.
Unlike most indicators that live in a separate pane below the chart, Bollinger Bands are plotted directly on price — which makes them unusually intuitive for beginners. You can see at a glance how far price is from its recent average and whether the market is currently calm or in a breakout.
Charted on TradingView — All Bollinger Band examples in this article are built on TradingView, the world's most popular charting platform. The indicator is free and available on any chart. Open TradingView free →
Key Concept: Bollinger Bands measure volatility, not direction. They don't tell you which way price will move — they tell you how much room it has to move and when a significant move is coming.
The Three Bands Explained
Every Bollinger Band chart has three components. Understanding what each one represents is the foundation of reading them correctly.
Middle Band (SMA 20)
20-period Simple Moving AverageThe baseline — where price "should" be on average over the last 20 periods.
When price is above the middle band, the short-term trend is up. Below it, the trend is down. The middle band also acts as a dynamic support/resistance level.
Upper Band
Middle Band + (2 × Standard Deviation)The statistical upper boundary — price is "unusually high" when it touches or exceeds this band.
Touching the upper band doesn't automatically mean sell. In a strong uptrend, price can "walk the upper band" — hugging it for days or weeks. Context is everything.
Lower Band
Middle Band − (2 × Standard Deviation)The statistical lower boundary — price is "unusually low" when it touches or falls below this band.
Touching the lower band in a downtrend is not a buy signal. Falling markets can walk the lower band just as rising markets walk the upper. Never buy just because price hits the lower band.
The Math Behind It: Standard deviation measures how spread out prices have been from the average. When prices are volatile (big daily swings), the standard deviation is high and the bands widen. When prices are calm, the standard deviation is low and the bands narrow. This is the "breathing" you'll see on every chart.
How to Read the Bands
There are three primary states of Bollinger Bands, each telling a different story about the current market:
The Squeeze
Bands narrow to their tightest point in months. Volatility has contracted to an extreme. This is the calm before the storm — a big move is building.
Band Walk
Price hugs the upper or lower band across multiple candles. This signals a strong trend — the market keeps pushing against one boundary.
Band Touch + Reversal
Price touches one band and immediately reverses toward the middle band. Most reliable in ranging, sideways markets with no clear trend.
%B — Where Is Price Within the Bands?
%B is a companion indicator that tells you exactly where price is relative to the bands on a 0–1 scale. It's available as a separate indicator on TradingView and is useful for spotting divergences and confirming setups.
%B = 1.0
Price is at the upper band
%B = 0.5
Price is at the middle band
%B = 0.0
Price is at the lower band
Trading Signals
Bollinger Bands generate four high-probability signals when combined with volume and a momentum indicator like RSI. Never trade any of these signals in isolation.
| Signal | What to Look For | Confirmation Needed | Reliability |
|---|---|---|---|
| Squeeze Breakout | Bands contract to multi-month low, then price breaks out sharply | High volume on breakout candle | High |
| Upper Band Walk | Price closes above upper band on 2+ consecutive candles | RSI above 50, rising volume | High |
| Lower Band Walk | Price closes below lower band on 2+ consecutive candles | RSI below 50, rising volume (downtrend continuation) | High |
| Double Bottom (W pattern) | Price touches lower band, bounces, retest doesn't break lower band | RSI oversold on 1st touch, higher low on RSI for 2nd touch | Medium |
| Upper Band Touch (range) | Price touches upper band in a flat, sideways market | Flat middle band, RSI overbought | Medium |
| Band Divergence | Price makes new high at upper band but RSI makes lower high | Declining volume on the second push | Medium-Low |
Add Bollinger Bands to Any Chart — Free on TradingView
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Settings & Customization
The default Bollinger Bands settings are 20 periods and 2 standard deviations. John Bollinger himself recommends starting with these defaults before experimenting. Here's how different settings change the behavior:
Period (default: 20)
Shorter period (10–15)
Bands react faster to recent price changes. More signals but more false positives. Better for short-term and day traders.
Longer period (30–50)
Bands react slowly. Fewer, higher-conviction signals. Better for swing traders and position traders.
Standard Deviations (default: 2)
Narrower bands (1.5)
Bands are tighter — price touches or breaches them more frequently. Can generate too many signals in volatile markets.
Wider bands (2.5–3)
Price only reaches the bands in extreme conditions. Signals are rarer but tend to be more significant, especially for breakout traders.
Recommendation: Start with the default 20/2 settings. Only adjust after you've spent time observing how price interacts with the bands across at least 50–100 bar examples. Changing settings without understanding the defaults first leads to over-optimization.
Common Mistakes Beginners Make
Mistake: Treating band touches as automatic buy/sell signals
Fix: Price touching the upper band is only a sell signal in a ranging market. In a trend, it's a continuation signal. Always identify the trend context first.
Mistake: Trading the squeeze without waiting for confirmation
Fix: A squeeze tells you a big move is coming — not which direction. Wait for price to break out of the squeeze range on high volume before entering. Many traders lose money buying or selling anticipating the breakout direction.
Mistake: Using Bollinger Bands alone
Fix: Bollinger Bands show volatility and extremes, not momentum or trend strength. Always combine with RSI (for momentum) and volume (for confirmation). The two classic combos: BB + RSI, or BB + MACD.
Mistake: Forgetting that bands auto-adjust to volatility
Fix: A "tight" band on a low-volatility stock and a "wide" band on a high-volatility stock can look the same visually but mean completely different things. Use the Bandwidth indicator to compare band width relatively, not visually.
Mistake: Applying the same strategy across all time frames
Fix: Mean-reversion strategies (buy lower band, sell upper band) work in ranging daily charts. They fail badly on 5-minute charts where trends dominate. Match your strategy to the market condition, not your preferred time frame.
Quick Reference Summary
Best Use Case
Identifying volatility cycles, squeezes, and trend strength
Default Settings
20-period SMA, ±2 standard deviations
Best Combination
Bollinger Bands + RSI (the most widely used pairing)
Avoid Using When
News events, earnings releases, or very thin volume sessions
Available On
Every major platform — free on TradingView by default
Inventor
John Bollinger, CFA — still actively publishes research on bbands.com
Want to go deeper? Our full indicator series covers how Bollinger Bands compare directly against RSI as a standalone indicator → Bollinger Bands vs RSI: Which Is Better?
Practice Bollinger Bands on Real Charts — Free
TradingView has Bollinger Bands built in. Add them to any chart in one click — stocks, crypto, forex, futures. Free plan, no credit card required.
Affiliate disclosure: clicking the links above may earn BrokerInsight a commission at no extra cost to you. All editorial recommendations are independent.
Bollinger Bands vs RSI: Which Is Better?
Now that you understand the bands, see how they stack up against RSI for overbought/oversold signals — and when to use both together.
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