Aroon Indicator Explained: Spotting New Trends by Timing the Last High or Low

Most trend indicators measure how far price has moved. Aroon measures something different: how long it's been since price last made a new high or a new low. That shift in perspective — time instead of magnitude — is what lets Aroon flag a fresh trend the moment it starts, often before an oscillator like RSI or a moving-average crossover has caught up.

Developed by Tushar Chande in 1995, "Aroon" comes from the Sanskrit word for "dawn" — the idea being that the indicator signals the dawn of a new trend. In crypto, where trends can ignite in a single 15-minute candle after weeks of chop, that early-warning property is genuinely useful.

How Aroon Is Calculated

Step 1 — Count Bars Since the Last High and Low

Over a lookback window (default 25 periods), Aroon finds two numbers: how many bars ago the highest high occurred, and how many bars ago the lowest low occurred.

Step 2 — Convert to a 0–100 Scale

Each count is normalized against the window length, so a high that happened this bar scores 100 and a high that happened 25 bars ago scores 0:

Two lines plot on the same 0–100 pane. Aroon Up near 100 means a new high just printed; Aroon Down near 100 means a new low just printed. As bars pass without a fresh extreme, that line decays linearly toward zero — which is why the lines look like sawtooth ramps rather than smooth curves.

Reading Aroon Signals in Practice

Above 70: A Trend Is Established

When Aroon Up holds above 70 while Aroon Down stays below 30, price has been repeatedly printing new highs and rarely testing new lows — a textbook uptrend. The mirror case (Aroon Down above 70, Aroon Up below 30) marks a downtrend. On BTC and ETH 1h charts, Aroon Up crossing above 70 has reliably coincided with the start of the sharpest legs of a move, well before a 20/50 EMA crossover confirms it.

Both Lines Below 50: Consolidation

When neither line can climb above 50, price isn't making meaningful new highs or lows in either direction — it's ranging. This is Aroon's other core use: filtering out chop before it drains a trend-following strategy. Many traders disable trend signals entirely while both lines sit under 50, and only re-arm once one line breaks decisively above 70.

The Crossover

When Aroon Up crosses above Aroon Down, buyers have taken over making the recent extremes; the reverse crossover flags sellers taking control. Crossovers near the 50 midline, while both lines are still climbing out of consolidation, tend to mark the earliest and most tradeable trend changes — a crossover happening after both lines already sit near 100 is much less informative, since the trend it's confirming is already mature.

The Aroon Oscillator and Combining With Other Tools

Subtracting Aroon Down from Aroon Up collapses both lines into a single oscillator between −100 and +100, which is easier to scan across a watchlist: positive and rising means strengthening uptrend, negative and falling means strengthening downtrend, and readings hovering near zero flag the same consolidation the two-line version shows.

Aroon + ADX: Aroon tells you a new trend has likely started; ADX tells you how strong it's become. Using Aroon for early entry timing and ADX to confirm the trend has real strength catches moves earlier without trading every minor Aroon crossover.

Aroon + Supertrend: Supertrend gives a clean directional bias with a visual stop level; Aroon crossing to confirm that same direction, rather than fighting it, filters out the whipsaws Supertrend alone produces in choppy conditions.

Aroon + Volume: A new-high spike in Aroon Up backed by above-average volume is a materially stronger signal than the same spike on thin turnover — pairing Aroon with OBV or CMF helps separate a real breakout from a low-liquidity wick.

On Strategester, Aroon runs alongside ADX, Supertrend, EMA, and 40+ other strategies across 32 crypto markets, with the live confluence score updating in real time as trend and momentum signals line up.