How is the Vortex Indicator calculated?

For each bar, positive vortex movement is the absolute distance from the current high to the prior bar's low, and negative vortex movement is the absolute distance from the current low to the prior bar's high. Each is summed over the lookback, commonly 14 bars, and divided by the sum of true range over the same window, producing VI+ and VI−.

Is the Vortex Indicator better than ADX/DMI?

Neither dominates. Both build paired directional lines from bar-to-bar range logic; DMI adds Wilder smoothing and the ADX strength line, which slows signals but filters chop, while the vortex pair reacts faster and crosses more often. Which behavior helps depends on how trendy the market is, so traders typically test both on their instrument rather than assume.

Why is it called the Vortex Indicator?

The authors drew the name from vortex motion in nature, water spiraling in a stream, air in a storm, and mapped the image onto bars: an advancing market keeps stretching from each high back over the prior low, an expanding upward spiral, while a declining one spirals the other way. The 2010 publication presented the two sums as measurements of those opposing spirals; the physics is decoration, the reach arithmetic is the indicator.

What does the 1.0 level mean on the vortex lines?

The lines are reach divided by true range, so a value near 1.0 means that direction's bar-to-bar reach has been running at roughly the full range the market traded over the window. One line holding above 1.0 while the other sits well below is a trending signature; both hugging 1.0 means the two reaches are canceling, the indicator's picture of indecision. Level conditions built on 1.0 are a common filter on raw crossings.

What lookback should the Vortex Indicator use?

The published default of 14 bars remains standard, with the usual trade: shorter windows cross sooner and whipsaw harder, longer ones, 21 and up, calm the pair at the cost of later turns. Because the indicator carries no internal smoothing, the lookback is doing all of the stabilizing work, which is why choppy instruments usually get the longer settings or an external smoothing pass.

Can the Vortex Indicator measure trend strength without direction?

Informally, through separation: the absolute gap between VI+ and VI− plays the strength role, wide gaps marking conviction and braided lines marking chop, regardless of which line is on top. Unlike the DMI family it offers no dedicated smoothed strength line, so systems wanting an explicit strength gate either compute the spread themselves or borrow ADX for that job while keeping vortex crossings for direction.

Concept

Vortex

Vortex is a Trend concept. The Library holds 1 implementation, a working definition you can pull into Quant.

VI+/VI−

The standard Vortex indicator

Vortex exactly as classically defined: the faithful reference build of the original formula, free to run in Quant.

Vortex Indicator

Indicator

What is the Vortex Indicator?

The Vortex Indicator (VI) is a two-line trend tool published by Etienne Botes and Douglas Siepman in 2010, named for an analogy to vortex flows observed in nature. The positive line, VI+, sums the absolute distances from each bar's high to the prior bar's low over the lookback; the negative line, VI−, sums the absolute distances from each bar's low to the prior bar's high; both sums are divided by the total true range over the same window, with 14 periods a common default. Upward bar-to-bar reach feeds VI+, downward reach feeds VI−, and the normalization keeps the pair comparable across volatility regimes.

Signals are read from the pair: VI+ crossing above VI− argues the uptrend has the upper hand, the opposite cross argues for the downtrend, and wide separation is taken as trend strength while braided, overlapping lines mark chop. It occupies the same niche as the ADX/DMI system but derives direction from bar-to-bar reach rather than Wilder's directional movement, and because it applies no Wilder smoothing and has no separate strength line, its crossovers tend to arrive faster and whipsaw more in ranges.

The authors introduced the indicator in a Technical Analysis of Stocks & Commodities article, crediting the inspiration to vortex motion in water and air: an uptrending market, in their analogy, keeps reaching from each bar's high back over the prior bar's low, tracing an expanding spiral upward, and the indicator simply measures the two spirals against each other. The normalization detail matters more than the poetry: dividing by summed true range converts raw reach into a proportion, so a reading near 1.0 says that direction's reach has been running close to the entire range the market traded, which is why both lines hovering around 1.0 reads as pure indecision.

The lack of smoothing is a deliberate temperament choice, and practice compensates externally. Common mitigations include longer lookbacks around 21 bars in choppy instruments, a light EMA pass over the lines, and demanding that a crossover coincide with a level condition, VI+ above 1.0 while VI− sits depressed, before honoring it. The Library's builds show the same instinct for reinforcement: pairings with a MACD histogram, with RSI, and as the directional gate inside a range-breakout system, each using the vortex pair for direction while something steadier vets the timing.

How to identify Vortex Indicator readings

Two sums, one normalization, and a small grammar of crossings, levels and separation.

1Compute per bar: positive vortex movement as the absolute distance from the current high to the prior low, negative as the distance from the current low to the prior high.
2Sum each series over the lookback, 14 bars classically, and divide both by the summed true range of the same window.
3Plot the pair: VI+ and VI− oscillating around the 1.0 area, where reach and range balance.
4Read crossings as direction-change candidates, separation as strength, and braided lines around 1.0 as chop to stand aside from.
5Filter the crossings: a higher-timeframe bias, a trend regime read, or a level requirement keeps range noise from spending your attention.

How it's calculated

Two lines, VI+ and VI-, that measure upward and downward trend strength from the reach between consecutive bars.

\operatorname{VM}^{+}_t = \lvert H_t - L_{t-1} \rvert

\operatorname{VM}^{-}_t = \lvert L_t - H_{t-1} \rvert

\operatorname{TR}_t = \max(H_t - L_t, \lvert H_t - C_{t-1} \rvert, \lvert L_t - C_{t-1} \rvert)

\operatorname{VI}^{+}_t = \frac{\sum \operatorname{VM}^{+} \text{ over the last } n \text{ bars}}{\sum \operatorname{TR} \text{ over the last } n \text{ bars}}

\operatorname{VI}^{-}_t = \frac{\sum \operatorname{VM}^{-} \text{ over the last } n \text{ bars}}{\sum \operatorname{TR} \text{ over the last } n \text{ bars}}

H_t: high of bar t

L_t: low of bar t

C_t: close of bar t

t: bar index (t-1 denotes the prior bar)

VM+_t: upward vortex movement at bar t

VM-_t: downward vortex movement at bar t

TR_t: true range of bar t

n: summing length (commonly 14)

VI+_t: positive vortex line at bar t

VI-_t: negative vortex line at bar t

Introduced by Etienne Botes and Douglas Siepman in 2010.

Both lines oscillate around 1; VI+ crossing above VI- is read as the start of upward trend pressure, and the opposite cross as downward.

How traders use it

As a trend-change trigger: crossovers of VI+ and VI− flag directional turns, usually filtered by a higher-timeframe bias or a smoothing pass because raw crosses are frequent in ranges.
As a strength gauge: the spread between the lines, or one line holding at an elevated level, qualifies whether a trend is worth following.
As confirmation for other systems, for example only honoring breakouts when the vortex pair already leans the same way.
With level conditions: requiring VI+ to hold above the 1.0 area while VI− stays depressed, rather than trading bare crossings, converts the pair into a trend-hold condition that survives minor rotations.
As the directional gate in breakout systems: range breaks are honored only when the vortex pair already leans in the break's direction, the construction used by the Library's vortex range-breakout build.

Vortex Indicator vs related trend tools

ADX/DMI System: Both pair directional lines built from bar-to-bar range logic. DMI adds Wilder smoothing and the ADX strength line, buying stability at the cost of speed; the vortex pair skips both, crossing faster and whipsawing more. Same niche, opposite temperament settings.

Supertrend: Supertrend outputs a stateful line that holds direction until price crosses an ATR band, a regime with memory. The vortex pair re-evaluates continuously and carries no ratchet, so it registers deterioration earlier while Supertrend ignores it longer. Gate versus gauge.

Moving Average Crossovers: MA crossovers compare two smoothed prices; vortex crossings compare two normalized reach sums. Both lag turns, but differently: averages lag by smoothing memory, vortex sums lag by window contents, and the vortex pair adds a strength read (separation) that a two-line MA cross lacks.

Concept family

Trend

100 concepts mapped · 100 in the Library

Vortex FAQ

Turn Vortex into a trading strategy.

Take the implementation from this page into Quant, then build on it, backtest it on real data, and keep refining it in conversation.

Previous conceptVolume-adjusted MA Next conceptVWMA