Decoded Intelligence Signal

+DI/-DI Lines

intermediate
technical_analysis
3 min read
354 words

Published Last updated

Key Takeaway

The +DI and -DI lines are the directional components of the Directional Movement System, measuring upward and downward price movement separately to indicate trend direction alongside ADX trend-strength readings.

Learn These First

What Is +DI/-DI Lines?

The +DI and -DI lines are the directional components of the Directional Movement System, measuring upward and downward price movement separately to indicate trend direction alongside ADX trend-strength readings.

How +DI/-DI Lines Works

The +DI and -DI lines — the Positive Directional Indicator and Negative Directional Indicator — are plotted alongside the ADX line and together form the complete Directional Movement System developed by J. Welles Wilder. While ADX measures how strongly price is trending, the DI lines answer the directional question: is that trend moving upward or downward? The +DI line measures the strength of upward price movement. It is derived from comparing the current bar's high against the previous bar's high — capturing the degree to which price is reaching higher highs. The -DI line measures the strength of downward price movement by comparing current lows against previous lows. Both values are smoothed using Wilder's smoothing method and expressed on a 0-to-100 scale. The relative position of the two lines indicates trend direction. When +DI is above -DI, upward directional movement is dominant — price is making more meaningful higher highs than lower lows, indicating a bullish trend environment. When -DI is above +DI, downward directional movement dominates, indicating a bearish trend environment. Wilder's original trading system used DI line crossovers as entry and exit signals. A +DI crossing above -DI generates a bullish signal; a -DI crossing above +DI generates a bearish signal. These crossovers are considered most actionable when accompanied by a rising ADX above 25, confirming that the directional shift is occurring within a genuine trending environment rather than in a low-conviction range. The spread between the two lines also provides additional insight. A wide separation between +DI and -DI, combined with high ADX, indicates strong directional conviction. A narrow spread — the lines running close together — suggests directional balance and typically corresponds to low ADX readings and ranging price behaviour.

Frequently Asked Questions

How do the +DI and -DI lines generate trading signals?

The primary signal from the DI lines is the crossover: when +DI crosses above -DI, it indicates that upward directional movement has become stronger than downward directional movement, generating a bullish signal. When -DI crosses above +DI, the reverse is true, generating a bearish signal. Wilder's original system entered long on a +DI crossover above -DI and exited or reversed on a -DI crossover above +DI. These signals become significantly more reliable when ADX is above 25 and rising, confirming that the crossover is occurring within a genuine trending environment rather than a directionless, choppy market phase.

Can the +DI and -DI lines be used without ADX?

The DI lines can technically be read without ADX, but doing so significantly reduces signal quality. DI crossovers occur frequently in both trending and ranging markets. In ranging conditions, the lines cross back and forth repeatedly without establishing sustained directional momentum, generating a series of false signals that can produce consistent small losses. ADX acts as the filter that distinguishes meaningful DI crossovers — those occurring when a real trend is developing — from random directional noise in low-momentum market phases. The Directional Movement System was designed as a three-component framework, and using only two components removes an important quality filter.

What does a very high +DI reading with a very low -DI reading indicate?

A very high +DI reading alongside a very low -DI reading indicates dominant, one-sided upward directional movement. Price is consistently reaching higher highs relative to previous highs, with minimal downward directional pressure. This configuration typically accompanies a high ADX reading, confirming a strong uptrend with clear directional conviction. The wider the spread between +DI and -DI in the upward direction, the stronger the evidence of bullish trend dominance. However, very wide spreads sustained over long periods can also indicate trend maturity, and traders should monitor ADX trajectory for signs that trend strength is beginning to peak.

Common Misconceptions About +DI/-DI Lines

Common Misconception

The +DI and -DI lines show whether an asset's price is rising or falling right now

Technical Reality

The +DI and -DI lines measure the relative strength of upward versus downward directional movement over a smoothed lookback period — they do not show instantaneous price direction. A +DI above -DI means that upward directional movement has been stronger than downward directional movement across the indicator's calculation window, indicating a generally bullish trend environment. It does not mean price is currently rising on this specific bar. Short-term pullbacks within an uptrend can occur while +DI remains above -DI, because the smoothing process prevents the indicator from reacting to every minor price fluctuation.

Common Misconception

A +DI/-DI crossover is a reliable standalone buy or sell signal

Technical Reality

DI crossovers generate many false signals when used without ADX confirmation. In ranging or directionless markets, the +DI and -DI lines oscillate around each other frequently, producing crossovers that do not develop into sustained trends. Treating every DI crossover as an actionable entry creates a system with high trade frequency but poor signal quality. Wilder's original framework explicitly required ADX context — ideally above 20 to 25 and rising — before DI crossovers were considered meaningful trend signals. The crossover alone confirms a directional shift; ADX confirms whether that shift is occurring within a genuine trending environment.

Common Misconception

+DI and -DI values above 50 indicate an extremely strong trend

Technical Reality

High absolute DI values reflect strong directional movement within the indicator's smoothed calculation, but DI readings should not be interpreted using threshold levels the way RSI or ADX readings are. The meaningful signals from DI lines come from their relative position to each other — which is above which — and from their crossovers, not from absolute threshold levels. ADX is the component of the Directional Movement System that provides the trend-strength quantification with threshold-based interpretation. Attempting to apply fixed significance thresholds to raw DI values produces misleading conclusions not supported by Wilder's original design.

Related Terms

Compare Adjacent Terms

Access Pro Research Infrastructure

Deciphering +DI/-DI Lines is just the first step. Apply for the Q3 2026 Beta to gain direct access to our 8-agent intelligence pipeline.