Bollinger Bands Explained
Bollinger Bands are one of the most widely used technical indicators in forex — and one of the most misunderstood. Developed by John Bollinger in the 1980s, they consist of a 20-period moving average flanked by two standard deviation bands. When price touches the outer bands, most beginners think it signals an immediate reversal. It does not.
How Bollinger Bands Are Constructed
Bollinger Bands have three components:
- Middle band: 20-period simple moving average (SMA)
- Upper band: 20-SMA + 2 standard deviations
- Lower band: 20-SMA − 2 standard deviations
Statistically, price stays within the bands ~95% of the time when using 2 standard deviations. The bands expand during high-volatility periods and contract during low-volatility (consolidation) phases.
Key settings: Most traders use 20,2 (default). Scalpers sometimes tighten to 10,2. Swing traders use 20,2 or 50,2 on daily charts.
What the bands tell you: Bandwidth = market volatility. Narrow bands = low volatility, often preceding a big move. Wide bands = high volatility, often near exhaustion.
The Bollinger Band Squeeze — Trading Breakouts
The squeeze is when the bands contract to their narrowest point in months. It signals that a big move is coming — but NOT which direction.
How to trade it:
1. Identify the squeeze (bands converging, bandwidth at multi-week low)
2. Wait for the breakout candle to close outside the band
3. Enter in the direction of the breakout on the retest of the band
4. Stop loss: below the opposite band or recent swing low
5. Target: 2× the bandwidth from the breakout point
Real example (EUR/USD, Jan 2025): EUR/USD squeezed for 3 weeks between 1.0230–1.0290. Breakout candle closed above upper band at 1.0350. Price ran to 1.0520 over the next 10 days — a 170-pip move.
The squeeze works best on daily and 4H charts. On 1M/5M charts there are too many false signals.
Band Bounce Strategy — Ranging Markets
In ranging (sideways) markets, price tends to bounce between the upper and lower bands. This is the classic mean reversion use of Bollinger Bands.
Rules:
- Only trade bounces when the middle band is flat (not trending)
- Buy: Price touches lower band + bullish reversal candle + RSI < 40
- Sell: Price touches upper band + bearish reversal candle + RSI > 60
- Stop loss: just beyond the band that was touched
- Target: middle band (SMA 20)
Common mistake: Trading bounces in a trending market. When price rides the upper band in an uptrend, touching the upper band is NOT a sell signal — it is a sign of strength. Add a trend filter: only trade bounces if the ADX is below 25 (weak trend).
Bollinger Bands + RSI Combination
Bollinger Bands work best combined with a momentum indicator like RSI:
Setup (daily chart):
- BB 20,2 + RSI 14
- Buy signal: price closes below lower BB AND RSI is below 30 (oversold)
- Sell signal: price closes above upper BB AND RSI is above 70 (overbought)
- Confirmation: next candle reverses back inside bands
This combination significantly reduces false signals. Without RSI confirmation, lower band touches in downtrends can produce 3–5 consecutive losses before a reversal occurs.
Pairs that work well: EUR/USD, AUD/USD, USD/JPY on H4 and daily charts. Avoid JPY crosses in high-carry environments — the trend often overrides the mean reversion signal.
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