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Understanding Average True Range (ATR)

The Average True Range (ATR) is a crucial technical analysis indicator used in financial markets to measure market volatility. Developed by J. Welles Wilder Jr. and introduced in his 1978 book, “New Concepts in Technical Trading Systems,” the ATR has become a fundamental tool for traders and analysts. This article delves into the intricacies of ATR, its calculation, significance, and its application in trading strategies.

What is Average True Range?

The ATR quantifies exchange rate volatility by analyzing the range of price movements over a specified period. Unlike other indicators that focus on price direction, ATR solely measures volatility. This makes it invaluable for traders who need to understand the degree of price fluctuations in an asset.

How is ATR Calculated?

The ATR calculation involves three steps:

  1. True Range (TR) Calculation: The True Range for each period is determined by the greatest of the following:
    • The difference between the current high and the current low.
    • The difference between the current high and the previous close.
    • The difference between the current low and the previous close.
    Mathematically, it can be represented as:TR=max⁡(High−Low,∣High−Previous Close∣,∣Low−Previous Close∣)TR = \max(\text{High} – \text{Low}, |\text{High} – \text{Previous Close}|, |\text{Low} – \text{Previous Close}|)TR=max(High−Low,∣High−Previous Close∣,∣Low−Previous Close∣)
  2. Initial ATR Calculation: The ATR is typically calculated over 14 periods. The initial ATR value is simply the average of the first 14 True Range values:Initial ATR=∑i=114TRi14\text{Initial ATR} = \frac{\sum_{i=1}^{14} TR_i}{14}Initial ATR=14∑i=114​TRi​​
  3. Subsequent ATR Calculation: Once the initial ATR is established, subsequent ATR values are calculated using the following formula:Current ATR=(Previous ATR×(n−1))+Current TRn\text{Current ATR} = \frac{( \text{Previous ATR} \times (n – 1)) + \text{Current TR}}{n}Current ATR=n(Previous ATR×(n−1))+Current TR​Where nnn is the number of periods (typically 14).

Significance of ATR

  1. Volatility Measurement: ATR provides a clear picture of market volatility. Higher ATR values indicate higher volatility, while lower values signify more stable market conditions.
  2. Risk Management: Traders use ATR to set stop-loss levels. By incorporating ATR into their risk management strategies, traders can account for market volatility and avoid being stopped out prematurely.
  3. Position Sizing: ATR helps determine appropriate position sizes. In highly volatile markets, traders may reduce their position size to mitigate risk, while in stable markets, they might increase their positions.
  4. Identifying Breakouts: ATR can help identify potential breakouts. Significant increases in ATR often precede major price movements, signaling that a strong trend may be developing.

Practical Applications of ATR

  1. Setting Stop-Loss Orders: One common method is the “ATR stop-loss,” where the stop-loss level is set at a multiple of the ATR below the entry price for long positions or above for short positions. For example, a stop-loss might be set at 1.5 times the ATR below the entry point for a long trade.
  2. Trailing Stops: Traders use ATR to trail stop-loss orders as the price moves in their favor. This technique allows for capturing more profit during strong trends while protecting against reversals.
  3. Position Sizing: By using the ATR to adjust position sizes, traders can standardize their risk across different trades. For instance, if a trader typically risks 1% of their capital per trade, they can use the ATR to determine the appropriate number of shares or contracts to trade, ensuring that each trade carries the same level of risk.
  4. Volatility-Based Entry and Exit: Some trading strategies involve entering or exiting trades based on changes in ATR. For example, a trader might enter a trade when ATR increases significantly, anticipating a strong price movement, and exit when ATR decreases, signaling reduced volatility.

ATR in Conjunction with Other Indicators

While ATR is powerful on its own, it is often used alongside other technical indicators to enhance trading decisions:

  1. Relative Strength Index (RSI): Combining ATR with RSI helps traders gauge both volatility and momentum. For example, a high ATR with an overbought RSI might signal a potential reversal.
  2. Moving Averages: ATR can be used to adjust moving average strategies. For instance, a trader might alter the length of the moving average based on current ATR levels to better capture market trends.
  3. Bollinger Bands: ATR can complement Bollinger Bands by confirming breakouts. If the price moves outside the bands and ATR is high, it suggests a strong trend.

Limitations of ATR

Despite its usefulness, ATR has some limitations:

  1. Lagging Indicator: ATR is a lagging indicator, meaning it reacts to past price movements. It does not predict future volatility but rather reflects current conditions.
  2. Sensitivity to Period Length: The choice of period length can significantly impact ATR values. While 14 periods are standard, traders may need to adjust this based on their specific strategy and market conditions.
  3. No Directional Bias: ATR measures volatility without indicating price direction. Traders must use other indicators or analysis techniques to determine the trend direction.


The Average True Range is a versatile and widely-used indicator in technical analysis, providing invaluable insights into market volatility. By understanding and applying ATR together with macro ecnomic indicators such as balance of payments, traders can improve their risk management, position sizing, and trading strategies. While it has its limitations, ATR’s ability to quantify market volatility makes it an essential tool for traders across various markets.

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