Trend & directionVortex Indicator · VI
Two crossing lines (VI+ and VI−) that capture the tug-of-war between upward and downward trend movement.
Works best in trending marketsEngine-computed on a fixed sample series
What it is
The Vortex Indicator is a trend tool that tries to capture the moment a market stops rotating one way and starts rotating the other, the way water swirling in one direction can flip and swirl the other. It was created by Etienne Botes and Douglas Siepman and published in Technical Analysis of Stocks and Commodities in 2010, inspired by the idea of vortex motion in flowing water. It plots as two lines: VI plus, which measures upward trend movement, and VI minus, which measures downward trend movement. The single question it answers is which force is currently stronger, the buyers driving price up or the sellers driving it down, and by how much. For a beginner, think of it as two competing runners on the same track, and the crossover of the lines is the moment one overtakes the other.
How it is calculated
Each bar produces two vortex movements. Positive vortex movement is the absolute distance from the current bar's high to the previous bar's low, capturing how far price reached upward relative to where it had been. Negative vortex movement is the absolute distance from the current bar's low to the previous bar's high, capturing the downward reach. Both of these are summed over a lookback window, commonly fourteen periods, and each sum is then divided by the sum of the true range over the same window, where true range is the standard measure of a bar's full span including any gap. VI plus is the summed positive vortex movement divided by the summed true range, and VI minus is the summed negative vortex movement divided by the summed true range. Normalizing by true range makes the two lines comparable across instruments and volatility regimes, and it keeps them hovering around one rather than growing without bound.
Reading it, step by step
The core reading is positional: when VI plus is above VI minus the market is in an uptrend, and when VI minus is above VI plus it is in a downtrend. The primary trigger is the crossover, the bar where the two lines swap places, which is read as the trend potentially changing hands. The second thing to read is the gap between the lines, because a wide separation signals a strong, one-sided trend while lines braided close together signal indecision or a range. Values themselves cluster around one, so a VI plus stretching toward 1.2 or higher while VI minus sags toward 0.7 describes a firm uptrend. When both lines converge near one and keep tangling, the market is telling you there is no reliable directional edge right now.
Best timeframes and settings
The default lookback is fourteen periods, which the authors used in their original work, and it suits daily swing trading well. Botes and Siepman noted that shorter lengths such as fourteen give more, earlier signals while longer settings such as twenty-one or thirty produce fewer, more reliable crossovers, so the parameter is a direct responsiveness dial. On intraday charts scalpers sometimes drop the length to catch faster rotations, accepting more whipsaw, while position traders lengthen it to smooth out noise. The indicator can be applied across all timeframes because its normalization by true range makes it scale-independent, but its signals are only as trustworthy as the trend behavior of the timeframe you choose. As always, a shorter window fires sooner and lies more often, and a longer window confirms later but with fewer false starts.
When and where to use it
The Vortex Indicator is built for trending markets and is at its best when you are trying to catch the beginning of a fresh directional move rather than trade an established range. It works across asset classes, from equities and futures to foreign exchange and crypto, because its true-range normalization adapts to each instrument's volatility. It is especially handy as a trend-entry timing tool layered on top of a market you already believe is starting to move. Where it struggles, and where you should be cautious, is in flat, sideways conditions, because the two lines will cross back and forth repeatedly and hand you a string of losing signals. The authors themselves recommended pairing it with a trend-strength gauge so that you simply skip crossovers that occur while the market is going nowhere.
Strategies that use it
The basic strategy is the crossover system: go long when VI plus crosses above VI minus and reverse to short when VI minus crosses above VI plus, treating each cross as a stop-and-reverse signal in a trending instrument. Because raw crossovers whipsaw in ranges, a stronger version adds a filter: only take the long cross when the Average Directional Index is above roughly twenty, confirming a real trend, and ignore crosses while it is below. A third approach uses the Vortex as an entry timer within a higher-timeframe bias, taking only the VI plus crosses when the weekly or daily trend is up and only the VI minus crosses when it is down, which cuts the countertrend noise dramatically. In each case, stops sit beyond the swing that preceded the crossover, and exits come either on the opposite cross or when the line separation collapses back toward one, signaling the trend is losing its grip.
Combining it with other indicators
The natural companion is the Average Directional Index, because it measures trend strength without direction and so tells you whether a Vortex crossover is worth trusting. It also pairs cleanly with the full Directional Movement system, since both descend from the idea of comparing upward and downward movement, though you should treat them as related cousins rather than independent confirmations. A moving average adds simple trend context, letting you filter crosses to those aligned with the slope of price. Momentum oscillators such as the Relative Strength Index or MACD can confirm that the new direction has momentum behind it, not just a mechanical line swap. Volume tools help too, since a Vortex cross accompanied by a surge in participation is more likely to mark a genuine trend change than one on quiet, disinterested tape.
Where it fails
Its defining weakness is the sideways market, where VI plus and VI minus cross repeatedly and every cross is a whipsaw that bleeds a mechanical trader dry. Because the signal only arrives on the crossover bar, there is inherent lag, and by the time the lines swap the first leg of the move may already be spent. The indicator has no notion of overextension, so it will keep you in a trend that is about to snap back with no warning. A common mistake is trading every cross in isolation without a trend-strength filter, which the authors explicitly cautioned against. Another is applying it to erratic, low-liquidity instruments where the bar-to-bar high and low relationships are noise. The remedy is discipline: require a trend filter, ignore crosses during compression, and size positions so the inevitable whipsaws are survivable.
A worked example
Imagine a stock that has been drifting sideways, with VI plus at about 0.95 and VI minus at about 1.05, so the down-rotation has a slight edge and the lines are close, warning of no clear trend. A catalyst hits and price breaks higher for several sessions. Over the fourteen-bar window the summed positive vortex movement climbs to, say, 14.0 while the summed true range is 15.0, lifting VI plus to about 0.93, and the summed negative vortex movement falls to 10.5, dropping VI minus to about 0.70. VI plus has now crossed above VI minus and the gap has widened to more than 0.20, describing a firm new uptrend. You check the Average Directional Index and find it has risen through twenty-two, confirming real trend strength, so you take the long on the crossover with a stop below the breakout bar's low. You plan to exit when VI minus eventually crosses back above VI plus or when the two lines collapse together toward one.