ADX is used to quantify trend strength. ADX calculations are based on a moving average of price range expansion over a given period of time. The default setting is 14 bars, although other time periods can be used. ADX can be used on any trading vehicle such as stocks, mutual funds, exchange-traded funds and futures.
ADX is plotted as a single line with values ranging from a low of zero to a high of 100. ADX is non-directional; it registers trend strength whether price is trending up or down. The indicator is usually plotted in the same window as the two directional movement indicator (DMI) lines, from which ADX is derived.
When the +DMI is above the -DMI, prices are moving up, and ADX measures the strength of the uptrend. When the -DMI is above the +DMI, prices are moving down, and ADX measures the strength of the downtrend.
ADX values help traders identify the strongest and most profitable trends to trade. The values are also important for distinguishing between trending and non-trending conditions. Many traders will use ADX readings above 25 to suggest that the trend is strong enough for trend-trading strategies. Conversely, when ADX is below 25, many will avoid trend-trading strategies.
ADX Value Trend Strength
0-25 Absent or Weak Trend
25-50 Strong Trend
50-75 Very Strong Trend
75-100 Extremely Strong Trend