ADX, or Average Directional Index, estimates trend strength. It does not by itself tell you whether the trend is up or down. Direction is commonly studied with the related +DI and -DI lines.
ADX measures strength, not direction
ADX rises as a trend strengthens. +DI and -DI help describe whether upward or downward directional movement is stronger.
What ADX measures
ADX usually moves between 0 and 100. Low readings suggest weak or sideways movement. Higher readings suggest a stronger trend, regardless of direction.
Common reference levels
Many traders use 20 or 25 as a rough trend-strength threshold, but the best threshold depends on the symbol, timeframe and strategy.
- Below 20: often interpreted as weak trend conditions.
- 20 to 25: transition zone.
- Above 25: often interpreted as stronger trend conditions.
How +DI and -DI add direction
When +DI is above -DI, upward directional movement has recently been stronger. When -DI is above +DI, downward directional movement has been stronger. ADX shows the strength of that directional movement.
Using ADX as a filter
ADX is often more useful as a confirmation rule than as a stand-alone entry. A strategy may require EMA alignment plus ADX above a threshold to avoid some sideways-market signals.
Frequently asked questions
Is high ADX bullish?
No. High ADX means the trend is strong. The trend may be upward or downward.
What ADX setting is common?
ADX14 is a common default, but thresholds and periods should be tested.
Can ADX reduce false crossovers?
It may filter some low-strength conditions, but it can also enter later and miss early parts of a move.