AlgoLiftAlgoLiftGuide

Aroon

Measures time since the highest high and lowest low over the lookback. Two lines (Aroon Up and Aroon Down) that signal trend strength based on recency of extremes.

IndicatorBy AlgoLiftUpdated 3 min read
On this page 13What it measuresFormulaInputs in AlgoLiftRecommended periodsOutputs in AlgoLiftHow to read itBest in / worst inThree setups1. Strong trend identification2. Aroon crossover entry3. Direction as a regime gateAdvanced patterns in AlgoLiftCommon mistakes

A trend indicator that measures how recently the highest high and lowest low occurred within the lookback window. Aroon Up is high when the period's high happened recently; Aroon Down is high when the low happened recently. Reading the gap between them tells you which direction is currently dominant.

What it measures

  • Time since the recent high (Aroon Up). 100 means the highest high just occurred; 0 means it occurred period bars ago.
  • Time since the recent low (Aroon Down). Same logic for the period's low.
  • Trend dominance. When Up is near 100 and Down is near 0, the trend is strongly up. When Down is near 100 and Up is near 0, strongly down.

Formula

Inputs in AlgoLift

SettingDefaultRangeNotes
Period142–500Lookback for finding the highest high and lowest low.
  • 7–9 (fast): Short-term trend detection.
  • 14 (default): Standard.
  • 25: Chande's original recommendation — slower, swing-friendly.

Outputs in AlgoLift

HandleTypePlottedNotes
Aroon UpNumericAlways0-100. High values = recent high is recent.
Aroon DownNumericAlways0-100. High values = recent low is recent.
OscillatorNumericOn selectAroon Up − Aroon Down. Range −100 to +100.
DirectionNumericOn select1 when Up > Down, −1 otherwise.

How to read it

  • Aroon Up > 70 AND Aroon Down < 30: Strong uptrend — new highs are still happening recently.
  • Aroon Down > 70 AND Aroon Up < 30: Strong downtrend.
  • Both lines near 50: Indecisive market.
  • Aroon Up crossing above Aroon Down: Trend direction has shifted bullish.
  • Aroon Up crossing below Aroon Down: Shifted bearish.
  • Both lines below 50: No recent extremes — sideways or weak trend.

The oscillator output (Up − Down) condenses both lines into one number: above 50 = strong up bias, below −50 = strong down bias.

Key Takeaway

Aroon answers a specific question: "did the recent high or recent low happen more recently?" That's a different question from "is price moving" — and Aroon's answer often lags ADX or Vortex by a bar or two, but it's also less prone to noise spikes since it requires actual new extremes.

Best in / worst in

Best in trending markets where new highs/lows happen regularly. Particularly useful as a confirming indicator alongside another trend tool — Aroon's "recent extreme" reading is robust against price noise that doesn't actually print new highs/lows.

Worst in range-bound markets (Aroon Up and Down both hover near 50, no clear signal) and on instruments with frequent gaps that produce artificial highs/lows.

Three setups

1. Strong trend identification

Trade only when Aroon shows extreme dominance.

  • Long: Aroon Up > 70 AND Aroon Down < 30 AND price > EMA(50).
  • Short: Aroon Down > 70 AND Aroon Up < 30 AND price < EMA(50).

The dual-extreme requirement ensures the trend is genuinely strong, not just marginally bullish.

2. Aroon crossover entry

Trade the line crossover with a confirmation filter.

  • Long: Aroon Up crosses above Aroon Down AND ADX/DMI > 20 (trend strength confirmation).
  • Short: Aroon Down crosses above Aroon Up AND ADX > 20.

The ADX filter is essential. Aroon crossovers in chop produce continuous whipsaws.

3. Direction as a regime gate

Use Direction output as a binary regime classifier for unrelated strategies.

  • Long-only mode: Direction = 1.
  • Short-only mode: Direction = −1.

Advanced patterns in AlgoLift

Aroon Oscillator for trend exhaustion exits. The Oscillator output (Up − Down) ranges −100 to +100. Set an exit condition that fires when Oscillator first drops below 50 in a long position (or above −50 in a short) — signals that the trend is losing dominance. Wire via Set Exit Condition.

Aroon and ADX combo for high-conviction trend entries. Aroon tells you when extremes are recent (trend direction is clear); ADX tells you when the trend is strong. Requiring both — Aroon Up > 70 AND ADX > 25 for longs — produces fewer but much higher-quality signals.

Multi-timeframe Aroon agreement. Add a 1h data series alongside your 5m execution chart. Only allow entries when both timeframes' Aroon agree on direction (both Up > Down, or both Down > Up). Cross-timeframe trend agreement is one of the most robust filters available.

Common mistakes

  • Reading Aroon as a momentum indicator. Aroon measures time-since-extreme, not rate-of-change. A trending market can have Aroon Up at 90 even while price is moving slowly — the indicator doesn't capture speed.
  • Trading crossovers without a regime filter. Aroon crossovers in chop fire continuously. Always pair with ADX or KAMA's ER.
  • Using Aroon on gap-prone instruments. A single overnight gap can produce a new "high" that drives Aroon Up to 100 even without any meaningful trend.
Common Misconception
Myth
Aroon predicts trend reversals.
Reality
Aroon describes whether the recent high or low is more recent — that's a current-state measurement, not a forecast. Aroon Up crossing above Aroon Down means the high just became more recent than the low; whether the trend continues is determined by what happens *next*, not by the crossover itself.

Next: TRIX