Technical analysis · updated October 21, 2026
What is ADX (average directional index)
ADX measures how strong the price trend is, on a scale from 0 to 100, regardless of whether the price is going up or down. Below 20 the market has no direction; above 25 there is a clear trend.
ADX formula
ADX=14-day average of DX
DX = |+DI − −DI| ÷ (+DI + −DI) × 100
- +DI
- How strong the upward moves were over the last 14 days.
- −DI
- How strong the downward moves were.
- DX
- The gap between the two, as a percentage of their sum.
How to read ADX
Below 20no trend
20 - 40a clear trend
Above 40a very strong trend
Read ADX together with direction: if +DI is above −DI, the strong trend is upward.
When ADX can fool you
It does not show direction: an ADX of 45 can also mean a crash.
Related terms
Questions about ADX
What is ADX used for?
To know whether trend indicators (averages, MACD) are worth following, or whether the market is flat and they give false signals.
These explanations are for information only. They are not a recommendation to buy or sell.
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