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ADX, DMI and trend strength
Updated 4 August 2026 · 3 min read · 14 Contents
Plain-language meaning
Directional Movement Index compares smoothed positive and negative directional movement, while Average Directional Index smooths their relative separation into trend-strength magnitude. ADX itself does not say whether the trend is upward or downward.
Learning objectives #
You should be able to distinguish +DI, −DI and ADX, outline the two-stage Wilder warm-up and reject the common mistake of calling high ADX bullish.
Core concept #
For each bar, compare upward and downward movement under directional-movement rules, smooth +DM, −DM and true range, form +DI and −DI, calculate DX from their absolute difference relative to their sum, then Wilder-smooth DX into ADX. XMarketRadar requires the second warm-up period before ADX is available.
Method and conventions #
Read direction from the +DI/−DI relationship and strength from ADX separately. If using a threshold, define crossing versus continuing-above state. Avoid counting +DI dominance and a price-derived trend label as independent votes without examining overlap.
Use it in XMarketRadar #
Add ADX/DMI in charting or use its documented screener field. Confirm period and sufficient history. Inspect price structure because a high ADX can accompany either a rise or a decline.
Worked example #
If +DI=30 and −DI=10, directional balance favours positive movement and DX=|30−10|/(30+10)×100=50 before smoothing. An ADX of 35 describes a comparatively strong directional regime under that sample, not an upward direction by itself.
How to interpret it #
Rising ADX means the smoothed directional separation is increasing; falling ADX means it is narrowing. +DI above −DI supplies the formula's positive direction component. Neither relationship guarantees continuation.
Limitations and common mistakes #
Do not interpret ADX sign—it is non-negative—skip its long warm-up, or treat 20/25 thresholds as universal laws. In a range, repeated DI crossings can create noise; after a sharp move, ADX can remain high while price consolidates.
Market-specific differences #
Typical ADX distributions differ with instrument volatility, session structure and interval. Compare thresholds only after matching parameters and market context.
Key takeaway #
Key takeaway: DMI describes directional balance and ADX describes the strength of that separation. Strength is not direction.
Practice exercise #
Practice: calculate DX from supplied DI values, classify direction and strength separately, then identify whether a threshold observation is a fresh cross or a continuation.
Educational use only #
This chapter is descriptive education. It is not investment advice, a price prediction, a recommendation, a claim of predictive accuracy, or an instruction to buy, sell, rebalance or place an order.