Understanding the ADX Indicator: A Comprehensive Guide

In trading, you often come across various tools and techniques, but few are as recognised as the ADX indicator. It’s been around since the late 1970s, thanks to J. Welles Wilder Jr. From stock markets to commodities and forex, it’s gained a solid footing almost everywhere.

So, what makes the ADX indicator so special? Well, its crux lies in determining the strength and direction of a trend. This makes it a handy tool to pinpoint when to enter or leave the market.

Read on to know more about ADX Indicator.

What is the Average Directional Index (ADX)?

Introduced in the 1970s, the ADX has been a cornerstone in technical analysis. It’s a key component of the Directional Movement System, which can be broken down into three segments: ADX, Positive Directional Index (+DI), and Negative Directional Index (-DI). 

An interesting aspect of the ADX line is that it doesn’t tell you the trend’s direction. Instead, it’s all about the trend’s strength. The ADX is gauged on a scale that ranges from 0 to 100. A high number? That’s indicative of a robust trend. On the flip side, a low number suggests a trend that’s not so strong.

Formula of ADX

The formula of ADX is a key component in understanding and utilizing this technical indicator. Also known as the Average Directional Index, it is calculated by taking the average difference between two directional movement indicators, the positive directional indicator (+DI) and the negative directional indicator (-DI). 

This is then divided by the sum of the two indicators and multiplied by 100 to give a percentage value. The resulting ADX value can range from 0 to 100, with higher values indicating a stronger trend. 

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The ADX is derived from two other indicators, the Positive Directional Indicator (+DI) and the Negative Directional Indicator (-DI). Here’s how it all comes together:

Calculate +DM and -DM (Directional Movement)

  • +DM is calculated as:

  • +DM = Today’s High – Yesterday’s High (only consider days where today’s high is greater than yesterday’s high)

  • -DM is calculated as:

  • -DM = Yesterday’s Low – Today’s Low (only consider days where today’s low is less than yesterday’s low)

Calculate the True Range (TR)

  1. True Range is the greatest of the following:

    • Today’s High – Today’s Low

    • Absolute Value (Today’s High – Yesterday’s Close)

    • Absolute Value (Yesterday’s Close – Today’s Low)

Smooth +DM, -DM, and TR

The smoothed values are typically calculated using a 14-period average.

Calculate the Directional Indicators (+DI and -DI)

  • +DI = (Smoothed +DM / Smoothed TR) * 100

  • -DI = (Smoothed -DM / Smoothed TR) * 100

Calculate the DX (Directional Movement Index)

DX = (Absolute Value (+DI – -DI) / (+DI + -DI)) * 100

Calculate the ADX

The ADX is an average of the DX and is usually calculated over 14 periods:
ADX = [(Previous ADX * 13) + Current DX] / 14

Explanation of Terms

  • +DM and -DM (Positive and Negative Directional Movement)

    These measures compare today’s high and low to the previous day’s high and low to determine whether the movement is ‘positive’ or ‘negative’.

  • True Range (TR)

    It’s a measure of volatility. It is the greatest of the three measures: the current high minus the current low, the absolute value of the current high minus the previous close, or the current low minus the previous close.

  • +DI and -DI (Positive and Negative Directional Indicators)

    These indicators provide a sense of direction in the movement. When +DI is above -DI, the movement is typically bullish and vice-versa.

  • DX (Directional Movement Index)

    It quantifies the difference between +DI and -DI and scales it between 0 and 100.

  • ADX

    This takes the DX and smooths it to create a longer-term picture of trend strength. Values below 20 typically indicate a weak trend, while values above 40 suggest a strong trend.

Calculating the ADX

Let’s say you’re looking at the stock of Reliance Industries, a company in the Indian Stock Market. You want to see if its stock price is steadily up or down.

To do this, traders often use something called the ADX. 

Here, we’ll break it down using easy numbers:

Direction Indicators

These are “score points” for up and down movements.

  • The score for the upward movement is 28.

  • The score for the downward movement is 15.

Difference Score (DX)

We find out how big the difference is between the upward and downward scores. In our example, it’s roughly 30. This tells us there’s a slight upward trend for Reliance’s stock.

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Trend Strength (ADX)

We then look at how steady this upward movement has been over the last 14 days. For our example, the ADX is about 25.7.

Now, what does this number mean?

  • If the ADX is below 20: Reliance’s stock isn’t really moving up or down much. It’s stable.

  • If it’s above 40: The stock has a strong trend, either going up or down.

  • If it’s between 20 and 40: The stock is moving, but not too fast.

Interpreting Trend Momentum with ADX

The Average Directional Index (ADX) is a powerful tool for interpreting trend momentum in the financial markets. It is a technical indicator that measures the strength of a trend, regardless of whether it is bullish or bearish.

This makes it a valuable tool for traders, as it can help them identify the strength of a trend and make informed trading decisions based on this information. The ADX is often combined with other indicators for a more comprehensive market view.

Using ADX for Trading Strategy

Designed to quantify trend strength, it’s devoid of directional bias. When employed within a trading strategy, the ADX can elevate the precision and outcome of trading decisions.

Interpreting the ADX for Strategy Formulation

1. Gauge the Trend Strength

  • Under 20

    The ADX reading below 20 typically suggests no clear trend. In this scenario, traders might avoid entry into new positions since the market lacks a strong directional bias.

  • Between 20 and 40

    This is important for many traders. An ADX value in this range suggests a developing trend, whether bullish or bearish . Traders can consider this a green signal to potentially align their trades with the direction of the prevailing trend.

  • Above 40

    A reading over 40 signals a strong trend. However, it’s crucial to note that extremely high readings might also indicate an overextended trend, which could be nearing exhaustion. 

2. Incorporate Directional Indicators

Though ADX measures strength, combining it with its siblings, the Positive Directional Indicator (+DI) and Negative Directional Indicator (-DI) can provide the direction of the trend.

A typical strategy

  • When +DI crosses above -DI and the ADX indicates a strong trend (above 20), traders might consider entering a long position.

  • Conversely, when -DI is above +DI with a robust ADX reading, it could be an opportunity to either short the asset or exit long positions.

3. Set Protective Stops

An effective strategy also involves risk management. Using the ADX can assist in setting protective stops. When the trend starts to weaken (ADX declining), it might be time to tighten stops or consider booking profits.

Limitations of ADX

One limitation of ADX is its inability to provide information about the direction of the trend. While it can identify the strength of a trend, it does not specify whether the trend is bullish or bearish. This can confuse traders relying solely on the ADX indicator for their trading decisions.

Additionally, the ADX indicator is not suitable for use in sideways or choppy markets, as it tends to give false signals in these conditions. This is because the ADX indicator formula is based on a moving average, which can be affected by sudden price fluctuations in a range-bound market.

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Moreover, the ADX indicator is lagging, meaning it is based on past price data and may not accurately reflect the current market conditions. This can result in delayed or missed trading opportunities, especially in fast-moving markets. 

Traders should be cautious when relying solely on the ADX indicator and utilize other technical and fundamental analysis tools to confirm its signals and make well-informed trading decisions.

Average Directional Index vs. the Aroon Indicator

The Average Directional Index (ADX) and the Aroon Indicator are two popular technical indicators used in technical analysis. Both indicators are used to measure trend strength and identify potential trend reversals. While they share some similarities, they also have distinct differences that make them unique trading tools.

The ADX indicator, also known as the Average Directional Movement Index, is a trend strength indicator that measures the strength of a trend regardless of its direction. It is calculated using the ADX formula, which considers the difference between the +DI (positive directional indicator) and -DI (negative directional indicator). 

On the other hand, the Aroon Indicator is a momentum indicator that measures the time elapsed between highs and lows to determine trend strength and potential trend reversals. This difference in calculation methods highlights the key distinction between the two indicators – the ADX focuses on trend strength, while the Aroon Indicator focuses on momentum and potential trend changes.


The ADX indicator is a valuable tool for traders looking to identify and measure the strength of a trend. By understanding its components and how to interpret its readings, traders can make more informed decisions and potentially increase their profitability.


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