Learn how to read the ADX indicator step by step: the 25 trend line, +DI/-DI crossovers, the best ADX settings, and how to trade trending vs ranging markets.
The ADX indicator measures how strong a trend is on a scale of 0 to 100, not which direction it is going. You read it three ways: the value (above 25 means a trend is present), the slope (rising means strengthening), and the +DI/-DI lines that sit alongside it to show direction. This guide covers how to read each of those, how to trade ADX in trending versus ranging markets, the crossover signal, and the settings that actually matter.
The ADX indicator is read on three levels at once: where the value sits, which way it is sloping, and what the two directional lines around it are doing. Most traders only read the first and miss the other two, which is where the useful information lives.
The value tells you whether a trend exists. Above 25, a trend is generally present. Below 20, the market is ranging. The slope tells you what is happening to that trend right now: a rising ADX means the trend is strengthening, a falling ADX means it is fading, even if the number is still high. A reading of 40 that is falling is a weakening trend, not a strong one.
The third level is direction, which ADX itself does not give you. For that you read the +DI and -DI lines, covered below. Read together, these three levels turn a single number into a complete picture of trend strength and direction.
ADX values fall into broad bands. These are not hard rules, but they are the conventional reading that most traders and systems use as a starting point.
Below 20 is a weak or absent trend, where the market is ranging or consolidating. The 20 to 25 zone is ambiguous, a trend may be forming but has not confirmed. From 25 to 50 is a strong, established trend, the zone where trend-following approaches find their edge. Above 50 is a very strong trend, and readings above 75 are rare and often appear near exhaustion rather than at the start of a move.
The single most-used threshold is 25. It is the line most traders draw between "ranging" and "trending," and it is the default trend filter in most systematic strategies. Whether 25 is the right line for your market is worth testing, but it is the standard reference point.
ADX is one line of a three-line system called the Directional Movement Index (DMI). The other two lines, +DI and -DI, are where direction comes from. +DI measures the strength of upward movement; -DI measures the strength of downward movement.
The crossover is the signal traders watch. When +DI crosses above -DI, upward movement has become dominant. When -DI crosses above +DI, downward movement has taken over. The crossover marks a potential change in direction; the ADX line then tells you whether that direction has the strength behind it to be worth acting on.
This is the key to using the crossover well. A +DI/-DI crossover while ADX is below 20 is happening inside a range and tends to produce false signals. The same crossover while ADX is above 25 and rising is happening inside a real trend and carries far more weight. The crossover gives you direction; ADX tells you whether to trust it.
ADX is most useful as a filter that tells you which kind of strategy fits current conditions, rather than as a signal on its own. The two cases are opposite.
The market is trending, and trend-following approaches are favoured. Momentum entries, breakouts, and moving-average strategies tend to work because moves follow through. The +DI/-DI lines tell you which direction to trade. Counter-trend and mean-reversion setups fight the prevailing force here and tend to fail.
The market is ranging, and mean-reversion approaches are favoured. Buying near support and selling near resistance works because there is no strong directional momentum to break the range. Breakout strategies produce false signals in this environment, because price appears to break out and then snaps back inside the range.
This is why ADX pairs so naturally with a regime view. The number is not telling you to buy or sell. It is telling you which playbook the current market calls for.
The standard ADX setting is 14 periods, the value Welles Wilder specified when he introduced the indicator in 1978. It is the default on virtually every charting platform and the most widely used, which also makes it the most reliable reference because so many participants are watching the same thing.
Shorter settings such as 7 periods make ADX more responsive but noisier, producing more false readings. Longer settings such as 21 or 30 smooth the line and cut noise but lag further behind price. There is no universally best setting. The right answer depends on your timeframe and should come from testing on your specific market, with 14 as the sensible starting point rather than a number to change on instinct.
The most common mistake is treating ADX as a buy or sell signal. A rising ADX does not mean buy. It means a trend is strengthening, in whatever direction the +DI/-DI lines indicate. Used alone as an entry trigger, ADX is incomplete by design.
The second mistake is ignoring the slope. A high ADX value that is falling is a weakening trend, and entering a trend-following trade on a high but declining ADX often means arriving as the move ends. The third is reading ADX in isolation during news events, where a brief volatility spike can push ADX up momentarily without a real trend behind it.
ADX measures trend strength well, but trend strength is only one dimension of what a market is doing. A complete read of market state also needs directional momentum and the broader structure around price. ADX on its own can tell you a trend is strong while missing that it is about to break.
This is the idea behind a market regime: combining ADX with directional analysis and moving-average structure to classify the market as trending, ranging, or bearish as a single state. ADX is the trend-strength component of that classification. Reading it well is the foundation; combining it with the other inputs is what turns a number into a regime. You can see the live ADX for any major pair, alongside its full regime, using the free tools.
Read ADX on three levels. First the value: above 25 means a trend is present, below 20 means the market is ranging. Second the slope: a rising ADX means the trend is strengthening, a falling ADX means it is weakening even if the value is high. Third, direction, which comes from the +DI and -DI lines alongside ADX, not from ADX itself. Together these tell you whether a trend exists, whether it is gaining or losing strength, and which way it points.
A +DI/-DI crossover is strongest when it happens while ADX is above 25 and rising. When +DI crosses above -DI, upward movement is dominant; when -DI crosses above +DI, downward movement is dominant. The same crossover while ADX is below 20 is happening inside a range and tends to produce false signals, so the ADX level is what tells you whether to trust the crossover.
The standard and most widely used setting is 14 periods, as originally specified by Welles Wilder. Shorter periods such as 7 react faster but produce more noise; longer periods such as 21 or 30 are smoother but lag more. Start with 14 and only change it based on testing for your specific market and timeframe.
No. ADX measures trend strength, not direction, so it never gives a buy or sell signal on its own. It works as a filter that tells you which kind of strategy fits current conditions: trend-following when ADX is above 25, mean-reversion when it is below 20. Direction comes from the +DI and -DI lines, not from ADX.