Bollinger Bands: How to Read and Trade Them

Bollinger Bands are a volatility indicator made of three lines: a 20-period simple moving average in the middle, and an upper and lower band two standard deviations above and below it. The bands narrow when the market is quiet and widen when it is active. Traders use Bollinger Bands to spot volatility squeezes, judge whether price is relatively high or low, and tell a trend apart from a range.

Quick answer: Bollinger Bands are a volatility indicator created by John Bollinger in the 1980s, made of a 20-period simple moving average with bands two standard deviations above and below. Bollinger Bands are neither bullish nor bearish on their own. A close outside the bands after a squeeze, confirmed by follow-through and rising volume, signals a likely expansion in that direction.

Bollinger Bands are one of the core tools in our technical indicators guide. They work best as a map of volatility, not as a buy and sell signal generator.

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What are Bollinger Bands?

Bollinger Bands are a volatility envelope plotted around price, developed by John Bollinger in the 1980s. Unlike fixed-percentage envelopes, Bollinger Bands adapt to the market: the distance between the bands comes from the standard deviation of recent closes, so the bands expand when price swings widely and contract when price is calm.

Bollinger Bands tell you two things: band width shows volatility, and band position shows relative price. A close near the upper band is high relative to the last 20 periods; a close near the lower band is relatively low. That is not the same as "overbought" or "oversold", and the bands never tell you which way price goes next. Direction has to come from structure, momentum, volume, or a level.

How are Bollinger Bands calculated?

Bollinger Bands are calculated from a moving average and the standard deviation of closing prices over the same lookback:

1. Middle band: the 20-period simple moving average (SMA) of closes. Our guide to moving averages covers how the SMA works.
2. Standard deviation: the standard deviation of the same 20 closes, a measure of how spread out they are around their average.
3. Upper band: middle band plus 2 standard deviations.
4. Lower band: middle band minus 2 standard deviations.

Most closes fall inside the bands, so a close outside them is relatively unusual, though market prices are not normally distributed.

The standard setting of 20 and 2 is the right place to start. John Bollinger has suggested a slightly wider multiplier for longer lookbacks and a slightly narrower one for shorter lookbacks, but tuning settings until past signals look perfect is a fast route to an overfitted strategy. Test any change with proper backtesting.

What is a Bollinger Band squeeze?

A Bollinger Band squeeze is a period when the bands contract to their narrowest width in a while, showing that volatility has dried up. Quiet phases tend to give way to expansion, so traders watch squeezes as breakout setups.

After a rally and a pullback, price settles into a quiet range and the bands close in until they are only a narrow channel apart (the squeeze marker). On the next candle price breaks out above the upper band, the bands flare open, and price walks up along the upper band while the 20 SMA turns higher underneath.

A Bollinger Band squeeze says a bigger move is likely, not which way. Squeezes often produce a head fake, a short break in one direction that reverses into the real move. The break and the follow-through matter more than the squeeze itself.

How do you trade a Bollinger Band squeeze?

A Bollinger Band squeeze is traded by waiting for a confirmed break out of the quiet range, not by guessing the direction in advance.

1. Identify the squeeze. The bands are clearly narrower than in recent weeks and price is moving sideways. Bandwidth (below) makes this objective.
2. Mark the range. The high and low of the consolidation become your breakout levels.
3. Wait for a close outside the band and the range, ideally on rising volume. An intrabar poke is not enough.
4. Enter on the breakout close, or on a retest of the range edge with a limit order. Our guide to market vs limit orders covers the trade-off.
5. Place the stop back inside the range, beyond its midpoint or its opposite side.
6. Manage the trade. While price walks the band and the bands keep widening, the move is healthy. A close back inside the bands and below the middle line warns that the expansion is fading.

What does walking the bands mean?

Walking the bands means price keeps closing at or near the upper band in an uptrend, or the lower band in a downtrend, for many candles in a row. In the squeeze chart above, price rides the upper band after the breakout while both bands widen, which is what a strong trend looks like on this indicator.

Beginners often read an upper band touch as "overbought" and short a market that is trending hard. In a trend, band touches are a sign of strength, and pullbacks that hold the middle band are usually better entries than the touches themselves.

How do you use Bollinger Bands for mean reversion?

Bollinger Bands are used for mean reversion in ranging markets by fading moves to the outer bands and targeting a return to the middle band. This only works when the market is genuinely sideways: the 20 SMA is flat, the bands are roughly parallel, and price is bouncing between clear support and resistance.

1. Confirm the range: a flat middle band and at least two touches of each side.
2. Wait for price to reach an outer band near a horizontal level, and look for a rejection candle rather than buying the first touch.
3. Place the stop beyond the band extreme or the range level.
4. Take profit at or near the middle band. Check the numbers with our risk-reward ratio guide.

If the bands start to widen and price closes outside them with strong candles, the range is turning into a trend: stop fading.

What is a Bollinger Band W-bottom?

A Bollinger Band W-bottom is a double bottom where the first low closes at or below the lower band and the second low holds inside the lower band, even if price dips to a similar level. The second low is less extreme relative to volatility, which suggests selling pressure is fading.

1. The first low touches or closes below the lower band.
2. Price bounces toward the middle band.
3. The second low holds inside the lower band.
4. Confirmation comes when price closes above the high of the bounce between the two lows.

The mirror image at the upper band, an M-top, works the same way for bearish reversals. Both are versions of the classic double top and double bottom pattern, and the same rule applies: no confirmation, no pattern.

What are Bollinger Band width and %b?

Bollinger Band width and %b are two readings derived from Bollinger Bands that turn the picture into numbers.

• Bandwidth = (upper band minus lower band) divided by the middle band. A bandwidth reading at a multi-month low is an objective definition of a Bollinger Band squeeze.
• %b = (price minus lower band) divided by (upper band minus lower band). A %b of 1 means price is at the upper band, 0 the lower band, 0.5 the middle band. Readings above 1 or below 0 mean price closed outside the bands.

%b is handy for scanning many markets and for confirming W-bottoms: if the second low has a higher %b than the first, it is less extreme relative to volatility.

How do Bollinger Bands compare with ATR?

Bollinger Bands and the Average True Range both measure volatility, but they answer different questions. Bollinger Bands use the standard deviation of closes and sit on the price chart, so they show where price is relative to its recent range. ATR averages the true range of each candle, including gaps, and sits in its own panel, so it shows how far price typically moves per bar.

Here ATR(14) stays flat while the market is quiet, then rises as candle ranges expand, and a stop two ATRs below the close widens with it. Bollinger Bands are better for spotting squeezes and relative extremes; the ATR indicator is better for sizing stops in units of volatility. Many traders use both.

How do you combine Bollinger Bands with RSI or volume?

Bollinger Bands combine well with momentum and volume tools because the bands do not measure momentum or participation.

• With RSI: a lower band touch while the RSI indicator shows bullish divergence is a stronger mean reversion setup than a touch alone. In a trend, RSI holding above 50 while price walks the upper band supports staying with the move.
• With volume: a squeeze breakout on rising volume has more participation behind it than one on thin volume.

Charts summarise how participants are behaving, but fundamentals and flows matter too. A scheduled release can override any band reading, which is why it pays to understand fundamental vs technical analysis.

What are the most common Bollinger Bands mistakes?

The most common Bollinger Bands mistake is selling every upper band touch, and buying every lower band touch, regardless of trend. Other frequent errors:

• Treating touches as signals. Wait for a rejection, a level, or a confirmed break.
• Guessing the squeeze direction. Entering before the break exposes you to head fakes and liquidity sweeps.
• Ignoring the regime. Mean reversion rules lose money in trends, and band walk rules lose money in ranges.
• Over-optimising settings until the past looks perfect.

Can AI improve Bollinger Bands signals?

AI tools can scan hundreds of markets for Bollinger Band squeezes, %b extremes and W-bottom candidates far faster than a person can. Pattern-recognition scanners are useful for building a shortlist, as covered in our guides to AI trading signals and AI trading strategies.

Whether a market is ranging, or a squeeze is tight enough, involves judgement, and automated scanners produce plenty of false positives. Any AI-assisted Bollinger Bands approach still needs backtesting and a human deciding whether the setup fits the wider context.

How do you use Bollinger Bands in a prop firm challenge?

Using Bollinger Bands in a prop firm challenge is mostly about risk control. Velotrade, a multi-asset prop trading firm, runs simulated evaluations across crypto, forex, stocks, index ETFs and commodities, and two rules matter most.

• Size from the stop. Put the stop where the setup is invalidated, then size the position so the loss is a small, fixed share of the account. The position size calculator does the maths.
• Respect the daily loss limit. It resets at 00:30 UTC and is set from the higher of balance or equity at that time. Failed squeeze breakouts can come in clusters, so cap your attempts per day.
• Know your drawdown. The maximum drawdown is static, explained in our static maximum drawdown guide. It does not trail profits, but it is a hard line.

News trading is allowed, but bands can blow out on a release, so check the calendar first. Funded traders earn a profit split of up to 90%. Velotrade is an educational, simulated evaluation, and nothing here is investment advice. Compare plans on the challenges page.