Aroon

What is Aroon?

Aroon is a pair of lines Tushar Chande introduced in 1995 that measure time instead of magnitude. Aroon Up counts the bars since the highest high of the lookback window (25 periods is the common default) and rescales the count to 0-100, so a high printed this bar reads 100 and a high a full window old reads 0. Aroon Down does the same with the lowest low. The name comes from a Sanskrit word for the light of dawn, reflecting the goal of catching a trend near its start.

In an uptrend new highs keep arriving, so Aroon Up pins near 100 while Aroon Down decays; downtrends mirror this. Many platforms also plot the Aroon oscillator, Aroon Up minus Aroon Down, which swings between +100 and -100. Because the input is recency of extremes rather than size of moves, Aroon can flag a persistent grind that momentum tools understate, and both lines sagging together flags a trading range.

How traders use it

• As a trend-onset signal: Aroon Up crossing above Aroon Down (or the oscillator crossing zero) says highs are now fresher than lows, often used as breakout confirmation.
• As a strength read: Aroon Up holding above about 70 with Aroon Down below about 30 is the conventional description of an established uptrend, mirrored for downtrends.
• As a consolidation filter: both lines below 50 means neither a new high nor a new low has printed in half the window, a cue to shelve trend entries.