ADX indicator explained for forex and gold

Most indicators try to answer one of two questions: which way is the market going, or has it gone too far? The Average Directional Index, usually shortened to ADX, answers a different one. It asks how strong the current move is, whatever its direction. That sounds like a small difference, but it changes how you use almost every other tool on the chart.

A crossover strategy, a breakout entry or an oscillator signal behaves very differently in a strong trend than in a sideways market. The ADX gives you a way to tell the two apart with a number instead of a feeling. This guide explains how the indicator is built, what its levels mean, how the +DI and -DI lines fit in, and how the readings looked on real daily charts of EUR/USD and gold over the last six months.

What the ADX indicator measures

The ADX was developed by J. Welles Wilder and published in 1978, in the same book that introduced RSI and the average true range. Wilder wanted a way to filter markets: some of his methods worked well when prices trended and lost money when they did not, so he needed a gauge of trend strength.

The result is a line that moves between 0 and 100. Higher values mean the market is moving in one direction with more conviction. Lower values mean the movement is choppy, with highs and lows overlapping from one bar to the next. The key point is that the ADX has no direction. A strong fall and a strong rise both push it higher. To see which side is in control, you need the two companion lines, +DI and -DI, which are part of the same indicator.

If you have read our guides to RSI and the stochastic oscillator, think of the ADX as the context those tools are missing. An overbought reading in a weak, ranging market is a very different thing from an overbought reading when the ADX says a strong trend is under way.

How the ADX is calculated

Your charting platform will do the maths, but the steps explain why the line behaves the way it does.

1. Directional movement. For each bar, compare today's high with yesterday's high and today's low with yesterday's low. If the rise in the high is bigger than the drop in the low, that rise counts as positive directional movement (+DM). If the drop in the low is bigger, it counts as negative directional movement (-DM). Only one of them can be positive on a given bar; the other is zero.
2. Directional indicators. Smooth +DM and -DM over 14 bars and divide each by the 14 bar average true range. Multiply by 100 and you have +DI and -DI. Dividing by the ATR means the lines show directional movement as a share of the normal range, so they can be compared across markets.
3. DX. Take the difference between +DI and -DI, divide by their sum and multiply by 100. When one side dominates, DX is high. When the two lines are close together, DX is low.
4. ADX. Smooth DX over another 14 bars. That second round of smoothing is why the ADX moves slowly and why it always lags price.

Because the ADX is built from the ATR, it shares some of its logic. Our ATR guide explains the true range in detail, and the volatility glossary entry covers the wider idea.

Reading the ADX levels

There is no official scale, but most traders use a few rough bands. Treat them as starting points rather than rules.

• Below 20: a weak or absent trend. Prices are rotating inside a range or moving in short, overlapping swings.
• 20 to 25: a grey area. A trend may be forming or fading.
• Above 25: a trend is in place. A reading above 25 is the threshold most often used to say that trend following methods are worth considering.
• Above 40: a very strong, often extended move. Readings this high do not last long on daily charts.

The direction of the ADX line matters as much as its level. A rising ADX means the trend is gaining strength. A falling ADX means it is losing strength, even if the reading is still high and prices are still moving the same way. Many traders watch for the moment the ADX turns down from a high reading, because that often comes as the move starts to slow.

The +DI and -DI lines

The two directional lines tell you who is in control. When +DI is above -DI, upward movement has been stronger than downward movement over the lookback. When -DI is above +DI, sellers have had the upper hand.

A crossover of the two lines is the most common directional signal from the indicator. +DI crossing above -DI is read as bullish, and the reverse as bearish. On their own, these crossovers are noisy in a range, because the lines twist around each other. That is where the ADX line earns its place: a crossover that happens while the ADX is rising through 20 or 25 carries more weight than one that happens with the ADX flat at 15.

The width of the gap matters too. A wide gap between the two lines, with the ADX climbing, describes a market where one side is clearly winning. A narrow gap with a falling ADX describes indecision.

EUR/USD: the ADX in a clean downtrend

The first chart shows EUR/USD daily bars from late April to 23 October 2026, with a standard 14 period ADX underneath. The readings come straight from the data, not from a hand picked example.

Around 20 September the ADX moved back above 25 with -DI already well above +DI. Over the following weeks EUR/USD fell from roughly 1.148 to around 1.12, and the ADX kept climbing, peaking at about 52 on 14 October. That is an unusually high reading for a major pair on a daily chart. By 23 October the ADX had eased to about 48, with -DI near 25 and +DI near 11.

Two lessons stand out. First, the high ADX did not mean EUR/USD was about to reverse; it meant the downtrend was strong, and selling rallies worked better than trying to catch the low. Second, the ADX starting to slip from its peak lined up with the pair moving sideways near 1.12 in the second half of October. The trend had not turned, but it had slowed. Our EUR/USD pair page covers the drivers behind those moves.

Gold: trend legs and a quiet range

Gold makes a good second example because it switched between trends and ranges several times over the same six months.

From June to late July gold was falling, -DI was on top, and the ADX rose above 25 and peaked at about 38.5 on 20 July, with gold futures close to $4,016. The peak in the ADX came very close to the low of that leg. That is a common pattern: the indicator is often highest when a move is most stretched, just before it pauses.

On 5 August gold jumped from about $4,153 to about $4,305 and +DI crossed above -DI. The ADX, at about 24, was still below 25 because of its double smoothing. It only crossed 25 on 7 August, with gold near $4,400. The up leg ran to about $4,680 in late August, with the ADX peaking in the mid 30s.

From mid September to mid October the ADX stayed mostly between 15 and 21. Gold rotated in a range of roughly $4,100 to $4,425 on a closing basis, and the DI lines crossed several times. A trader using crossovers alone would have been whipsawed; one who waited for the ADX to confirm would mostly have stood aside. By 23 October the ADX was rising again, at about 24, with -DI near 29 and +DI near 11 as gold dropped towards $4,000. For live gold ideas, see our XAUUSD trade setups, and for a broader view the XAUUSD pair page.

Using the ADX as a filter for other tools

The most practical use of the ADX is to decide which kind of tool to trust. A simple split works for many traders:

• ADX rising above 25: favour trend tools such as moving averages, pullbacks to support or resistance in the trend direction, and breakouts. Treat overbought or oversold oscillator readings with suspicion.
• ADX below 20 and flat: favour range tools such as oscillators, mean reversion entries near the edges of the range, and tighter targets.
• ADX between 20 and 25: reduce size or wait for clearer evidence.

This is exactly where the ADX complements the rest of the series. MACD crossovers tend to work better when the ADX is rising, while Bollinger Band fades near the outer bands work better when it is low. If you want a refresher on reading trend direction itself, our lesson on trends and moving averages covers the basics.

Settings and timeframes

Wilder's default period is 14, and most platforms use it. Shorter settings, such as 7 or 10, make the ADX react faster but produce more false readings. Longer settings, such as 20 or 30, are smoother and slower. There is no setting that suits every market, and changing the period until old charts look good is a fast route to a method that fails in live trading.

The same 14 period ADX reads differently on different timeframes. On a 15 minute chart it can swing from 15 to 40 in a single session, especially around the London and New York opens. On a daily chart, as the examples above show, readings above 40 are rare and usually signal an extended move. Many traders check the daily ADX for context and use a lower timeframe only for timing.

Common ADX mistakes

• Reading a high ADX as bullish. A high reading only means a strong trend. In the EUR/USD example it described a strong fall.
• Treating a falling ADX as a reversal. A falling line means the trend is losing strength. Price may simply move sideways, as EUR/USD did near 1.12.
• Expecting early signals. The double smoothing makes the ADX slow. In the gold example it crossed 25 two sessions and about $250 after the move began.
• Trading every DI crossover. Crossovers in a low ADX market are often noise, as gold showed from mid September to mid October.
• Ignoring the news calendar. A central bank decision can turn a quiet market into a trending one in minutes, long before the indicator reacts.

Risk control when the ADX is high

Strong trends are attractive, but they also come with larger daily ranges. When the ADX is high, the ATR is usually rising too, which means a stop placed at a normal distance can be too close. The usual answer is to place the stop where the trade idea is proven wrong and then reduce position size so the money at risk stays the same.

Our free position size calculator and risk reward calculator handle that maths for you. The wider topic of risk per trade is covered in the risk management lesson. If you want to go deeper into indicators, volatility and building rules you can test, the Advanced course on our Forexuro trading course page includes a full module on volume, volatility and indicators. Trends also tend to form flags, wedges and other continuation shapes, which our Chart Patterns Playbook e-book covers pattern by pattern.

For daily notes on which pairs are trending and which are stuck in ranges, follow the Forexuro Telegram channel. It is free and it is where we flag key levels before major releases.

ADX checklist before you act on a reading

• Which timeframe am I reading, and does the daily ADX agree with it?
• Is the ADX rising, flat or falling, not just high or low?
• Which DI line is on top, and how wide is the gap?
• Does the tool I plan to use suit a trend or a range?
• Is there a major release in the next few hours that could change the picture?
• Have I sized the trade for the current range, not last month's?
• Where exactly is the level that would prove the idea wrong?

Official sources

Primary reference pages from regulators, central banks and official bodies on the topics in this article.

• BIS: Triennial Central Bank Survey of foreign exchange markets, 2025, the global data on foreign exchange turnover by currency and trading centre.
• LBMA Gold Price, the London benchmark price for gold in US dollars per troy ounce.
• FCA: permanent restrictions on the sale of CFDs to retail consumers, the UK leverage limits, margin close-out rule, negative balance protection and risk warnings for retail CFD trading.

Frequently asked questions

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