# Bollinger Bands

Bollinger bands measure the volatility of a market and help traders identify potential entry and exit points, as well as overbought and oversold conditions

9 minutes

#### What are Bollinger Bands?

Bollinger Bands, created by John Bollinger in the 1980s, have become a popular technical analysis tool for traders looking to identify trends, volatility, and potential entry and exit points in the market.

Comprised of three lines – a middle line and two outer bands – Bollinger Bands are an envelope indicator that uses a simple moving average (SMA) of the price to represent the trend direction, and standard deviation to represent market volatility.

Traders rely on the relative position of the price to the upper and lower bands to gauge market conditions, with the price close to the upper band indicating an overbought market that may soon reverse, and the price close to the lower band indicating an oversold market that may soon bounce back.

Widening bands signal more volatility and unpredictability, while narrowing bands suggest a more stable and predictable market. In this post, we’ll delve deeper into Bollinger Bands, including how they’re calculated and how traders can use them to improve their trading strategy.

Also see: Bollinger %BBollinger Band Width

#### How are Bollinger Bands computed?

To effectively use Bollinger Bands in your trading strategy, it is important to understand the calculation process involved. Bollinger Bands are composed of three lines: the middle line, which is typically a 20-day simple moving average (SMA), and the upper and lower bands, which are plotted at two standard deviations away from the middle line.

To calculate Bollinger Bands, you must first determine the 20-day SMA of the security or market you plan to trade. Then, calculate the standard deviation of the price over the same 20-day period. Finally, plot the upper and lower bands by adding and subtracting two standard deviations from the moving average.

The formula for calculating Bollinger Bands is:

Middle line = SMA of n periods
Upper band = Middle line + k * standard deviation of n periods
Lower band = Middle line – k * standard deviation of n periods

Here, n represents the number of periods used for the SMA and the standard deviation, and k is a constant that determines the width of the bands. The default values for n and k are 20 and 2, respectively, but they can be adjusted based on individual preferences and strategies.

#### How to interpret Bollinger Bands?

Traders can leverage Bollinger Bands to gain insights into the market. Here are some ways to interpret them:

Trend

The middle line of Bollinger Bands can indicate the direction of the overall trend in the market. If the middle line is trending upward, it suggests an uptrend; if it is trending downward, a downtrend; and if it is flat, the market may be consolidating.

Volatility

The width of the bands corresponds to the level of volatility in the market. Wider bands indicate higher volatility and more significant price movements, while narrower bands suggest a less volatile market with smaller price fluctuations. The bands can also expand or contract to reflect changes in volatility over time.

Entry and Exit Points

Bollinger Bands can help traders identify potential entry and exit points. If the price touches or crosses the upper band, the market is considered overbought, indicating a possible reversal or consolidation. If the price touches or crosses the lower band, the market is considered oversold, indicating a possible bounce or rally. However, traders should use other indicators or signals to confirm these scenarios before making trades.

#### How to use Bollinger Bands in trading?

Bollinger Bands are a versatile tool that traders can use to improve their trading performance and decision-making. Below are some common ways that traders can use Bollinger Bands to enhance their strategies:

Observe Price Action

Traders can monitor price action around the upper and lower bands to determine potential oversold or overbought conditions. If the price touches the upper band, this could indicate that the stock is overbought and may be due for a pullback. Conversely, if the price touches the lower band, it may be an indication that the stock is oversold and may be due for a bounce.

Traders can use Bollinger Bands to identify the direction and strength of the trend by observing how the price interacts with the middle line. If the price stays above or below the middle line for a prolonged period, this suggests a strong uptrend or downtrend. If the price crosses above or below the middle line frequently, this suggests a weak or sideways trend.

Spot Reversals

Traders can use Bollinger Bands to identify potential reversals in the market by looking for price patterns such as double tops, double bottoms, head and shoulders, etc. that occur near the upper or lower bands. These patterns suggest that the price has reached an extreme level and may change direction soon.

Identify Volatility Periods

Narrow bands indicate that the market is consolidating and preparing for a significant move. Wide bands indicate high volatility and momentum. Traders can look for price candles that close outside of the bands as a sign of a potential breakout in either direction.

Detect Breakouts

Traders can use Bollinger Bands to detect potential breakouts in the market by monitoring how narrow or wide the bands are. A break above the upper band may signal a continuation of the uptrend, while a break below the lower band may signal a continuation of the downtrend.

Use Bollinger Bounce

This strategy involves buying when the price bounces from the lower band and selling when the price bounces from the upper band. This works well in a range-bound or sideways market, but can be risky in a trending or breakout market.

Identify Squeeze Situations

Traders can use Bollinger Bands to identify squeeze situations in which both volatility and momentum are low. This indicates that a significant price movement is likely to happen soon, as the market cannot stay in a low-volatility state for too long. Traders can use other indicators such as volume or momentum oscillators to confirm the direction of the breakout.

Use Bollinger Bandwidth

One tool that traders can employ is the Bollinger Bandwidth, an indicator that calculates the percentage gap between the upper and lower bands. It can help traders identify periods of high and low volatility and potential trend changes. A low bandwidth indicates low volatility and a possible squeeze or consolidation phase. A high bandwidth indicates high volatility and a possible trend or breakout phase.

Confirm with Other Technical Analysis Tools

Bollinger Band Width is most effective when used in conjunction with other technical analysis tools such as moving averages, momentum indicators, or volume indicators. This can provide a more comprehensive view of the market and increase the accuracy of trading decisions.

Bollinger Bands are a versatile and powerful technical analysis tool that can help traders gain an edge in the market. However, they should not be used alone or blindly, as they are not infallible and may generate false or misleading signals. Traders should always combine Bollinger Bands with other tools such as trend lines, support and resistance levels, chart patterns, etc., as well as their own analysis and risk management skills.

#### Advantages and Limitations of Bollinger Bands

Bollinger Bands can be a useful tool in trading, but they have advantages and limitations to consider:

• Bollinger Bands offer a visual representation of price volatility, which can aid in identifying potential trading opportunities.
• They can help determine if a market is overbought or oversold, and possibly due for a pullback or reversal.
• Bollinger Bands can be used together with other technical analysis tools to get a more comprehensive view of the market.
• These bands can be applied to any financial instrument, including stocks, commodities, forex, and cryptocurrencies.
• The Bollinger Band Width indicator can gauge market volatility and help traders identify potential trend changes.

Limitations

• As Bollinger Bands rely on historical price data, they may not accurately predict future market movements.