Aroon

Aroon measures the freshness of extremes: how many bars have passed since the highest high and the lowest low of a lookback window, each rescaled to a 0-100 percentage. Aroon Up reads 100 when the window's highest high printed on the current bar and decays toward 0 as that high ages; Aroon Down does the same for the lowest low. Tushar Chande's design cares about how long ago the latest record printed, not how far price traveled — and this build is a plain, unmodified implementation of the original indicator with its classic default length of 14.

How to Trade the Aroon?

• Aroon Up holding near 100: new highs keep arriving within the window — the uptrend is active and persistent.
• Aroon Down holding near 100: fresh lows keep printing — the same persistence on the sell side.
• Aroon Up crossing above Aroon Down: highs are now more recent than lows, an early trend-shift cue best treated as a prompt for further checks rather than an order trigger.
• Both lines sagging mid-range: neither extreme is fresh — the market is drifting sideways and crossover signals will whipsaw.
• One line pinned while the other decays to 0: the strongest configuration — a one-sided market whose opposing extreme is a full window old.

Because only recency enters the formula, a slow creep to marginal new highs pins Aroon Up as hard as an explosive run — the reading is persistence, not force. Bullish Cross and Bearish Cross alert conditions fire when the two lines cross.

Aroon Settings

• Length (default 14): the lookback scanned for the highest high and lowest low. Shortening it makes the lines snap to every minor extreme, giving earlier but noisier crosses; lengthening it (25 is a popular slower choice) demands more durable extremes before the lines pin.

Frequently Asked Questions

What does Aroon tell me that ADX does not?

ADX gauges how much of recent movement is directional — a trend's force. Aroon asks only how recently the market managed a new high or low, so it catches slow, steady trends that force-based tools underrate and reacts to a fresh extreme sooner — while saying nothing about the size of the move.

What length works best?

The default 14 is a balanced starting point: fast enough to flag emerging trends, slow enough that one spike does not pin the lines for long. Shorter windows trade earlier signals for more whipsaw, longer windows the reverse — match the length to the swings you trade.

What is Aroon's main limitation?

It is magnitude-blind: a one-tick marginal high resets Aroon Up to 100 exactly as a limit-up bar would, and a line can move merely because an old extreme dropped out of the window while price stood still. Pair it with a force or slope measure before trading a cross.