Aroon: Spot New Trends Before They Accelerate
The Aroon indicator answers a deceptively simple question: how recently did this stock make a new high or low? If the 25-period high was just hit, the uptrend is fresh and strengthening. If the 25-period low was hit recently, sellers are still in control. Aroon is one of the cleanest early-trend detectors in technical analysis.
Aroon Up measures how recently (within the last 25 bars) price made a new 25-bar high. Aroon Down measures how recently it made a new 25-bar low. Both range from 0 to 100. Aroon Up > 70 = recent highs = uptrend. Aroon Down < 30 = pressure from prior lows is fading. The Aroon Oscillator (Up − Down) summarizes it in one number: above +50 = strong bullish momentum, below −50 = strong bearish momentum.
What does Aroon actually measure?
Aroon was developed by Tushar Chande in 1995. Unlike most momentum oscillators that track price change, Aroon tracks time — specifically, how long since the highest high and lowest low within a lookback period (default: 25 bars).
| Line | What it measures | Range |
|---|---|---|
| Aroon Up | How recently the 25-bar high was set. 100 = new high today, 0 = high was 25 bars ago. | 0–100 |
| Aroon Down | How recently the 25-bar low was set. 100 = new low today, 0 = low was 25 bars ago. | 0–100 |
| Aroon Oscillator | Aroon Up minus Aroon Down. Positive = bullish momentum, negative = bearish momentum. | −100 to +100 |
The formula is straightforward: Aroon Up = ((25 − bars since 25-bar high) / 25) × 100. An Aroon Up of 92 means the 25-bar high was hit just 2 bars ago. An Aroon Up of 4 means the high was set 24 bars ago — nearly a full period back, signaling the uptrend is stale.
What do different Aroon levels mean?
| Aroon Up | Aroon Down | Market condition | Implication |
|---|---|---|---|
| > 70 | < 30 | Strong uptrend | New highs recent, lows are stale. Best condition for longs. |
| > 70 | > 70 | Volatile / whipsaw | Both making new highs and lows. Market is chopping — reduce size. |
| < 30 | > 70 | Strong downtrend | New lows recent, highs are stale. Avoid longs, risk is to the downside. |
| < 30 | < 30 | Sideways consolidation | Neither highs nor lows are recent. Range-bound. Wait for breakout signal. |
| Rising toward 70 | Falling toward 30 | Trend emerging | Aroon crossing — watch for full bullish setup (Up > 70, Down < 30) to confirm. |
How does the Aroon Oscillator simplify everything?
The Aroon Oscillator is just Aroon Up − Aroon Down, condensed into a single line that ranges from −100 to +100. It strips away two-line analysis and gives you a quick momentum read.
When the oscillator crosses zero from below, Aroon Up has just overtaken Aroon Down — the same as a bullish Aroon crossover. This is the entry trigger. When it crosses zero from above, the trend has flipped bearish.
The Aroon crossover: your trend-change signal
The most actionable Aroon signal is a crossover — when Aroon Up crosses above Aroon Down (or the Oscillator crosses above zero). It tells you the dominant momentum has just shifted from bearish to bullish.
📈 Bullish crossover
Aroon Up crosses above Aroon Down (or Oscillator crosses above 0). New highs are being made more recently than lows. Look for Up > 70 and Down < 30 within a few bars to confirm the full setup.
📉 Bearish crossover
Aroon Down crosses above Aroon Up (or Oscillator crosses below 0). New lows are more recent than new highs. Avoid longs; the trend has shifted to sellers.
⚠ Both lines near 50
No crossover signal is reliable when both lines hover in the 40–60 zone. The stock is chopping. Wait for one line to break to 70+ or fall below 30 before acting on direction.
☰ Both lines low (< 30)
Quiet consolidation. Neither highs nor lows are being made. This is often a coiling pattern before a breakout — watch for Aroon Up to surge first as the tell.
Aroon vs. ADX: which do you use when?
Both Aroon and ADX are trend-detection tools, but they answer different questions. Understanding the distinction helps you use both correctly.
| Question | Use Aroon | Use ADX |
|---|---|---|
| Has the trend direction changed? | ✓ Yes — crossover signals trend flip | ✗ ADX doesn't show direction |
| How strong is the existing trend? | ✗ Aroon shows recency, not strength | ✓ Yes — ADX > 25 = strong trend |
| Is the trend early-stage or mature? | ✓ Yes — Aroon near 100 = fresh trend | Possible but less precise |
| Is this a ranging vs. trending market? | Partial — both lines low = consolidation | ✓ Yes — ADX < 20 = ranging |
The most powerful setup combines both: Aroon bullish crossover + ADX rising above 25. Aroon tells you the trend just started; ADX tells you it has real conviction behind it.
Five practical Aroon rules
- Aroon Up > 70 is the minimum for new longs. Anything below 70 means the 25-period high was set more than a week ago. The uptrend isn't fresh enough to chase.
- Wait for Aroon Down to drop below 30 before adding conviction. If both lines are above 50, the market is chopping — the "bullish" reading is partly an illusion.
- Use the crossover as your trigger, not the level. A crossover from a low base (both lines under 50 crossing into bullish territory) is more meaningful than one from high volatile territory.
- Aroon is early — it leads momentum, not follows it. Because it's time-based rather than price-based, it can signal a new trend 2–5 bars before both RSI and MACD confirm. That's a feature, not a bug — use it for early-stage entries.
- Pair with volume for confirmation. A bullish Aroon crossover with rising OBV or positive CMF is a significantly higher-probability setup than Aroon alone. Trend plus accumulation = institutional backing.
What the MadStocks Aroon Analyzer scores
When you run the Aroon Analyzer on any ticker, it checks five conditions and returns a score from 0 to 5:
| # | Signal | Pass condition | Why it matters |
|---|---|---|---|
| 1 | Strong Uptrend | Aroon Up > 70 | Recent highs are being made within the last 7 of 25 bars — the uptrend is fresh and active, not a stale memory. |
| 2 | Weak Downside | Aroon Down < 30 | The last 25-period low was set more than 17 bars ago — downside pressure has largely exhausted and sellers are losing ground. |
| 3 | Bullish Position | Aroon Up > Aroon Down | Bulls are making higher highs more recently than bears are making lows. The directional edge is clearly bullish. |
| 4 | Strong Momentum | Aroon Oscillator > 50 | Oscillator above +50 requires a large gap between Up and Down — this filters out marginal bullish readings and flags conviction moves. |
| 5 | Recent Bullish Crossover | Aroon Up recently crossed above Aroon Down | A fresh crossover is the Aroon entry trigger — the moment the trend switched from bearish to bullish. Recency matters: older crossovers have less edge. |
Analyze Aroon on Any Stock
See live Aroon Up, Aroon Down, and Oscillator readings, buy signal scoring, and a plain-English trend verdict — for any ticker.