Donchian Channels
The highest high and lowest low over a lookback period, forming a price range channel — the foundation of the original Turtle Traders' breakout system.
Description
Donchian Channels were developed by Richard Donchian and form one of the earliest systematic trend-following methods. The indicator is purely mechanical: it plots the highest high and lowest low over N periods, creating a channel that shows the current trading range. The Turtle Traders, trained by Richard Dennis and William Eckhardt in the 1980s, built their famous system around a 20-period Donchian breakout.
How It Works
Upper Channel = highest high over N periods. Lower Channel = lowest low over N periods. Middle Channel = (upper + lower) / 2. Default N = 20. When a new candle closes above the upper channel, price has just made a new N-period high. When it closes below the lower channel, price has made a new N-period low. The channel is a factual record of recent price extremes with no smoothing.
How to Read It
A close above the upper channel is a breakout — price is reaching a level not seen in the last N periods, which is the Turtle Traders’ buy signal. A close below the lower channel is a breakdown and their short signal. Within the channel, the middle line can act as a bias reference. The channel width reflects the total range traded in the period.
Common Uses
- Breakout entry signals (Turtle system: buy new 20-period high)
- Trailing stop using the opposite channel boundary
- Trend identification by position relative to the middle channel
- Setting initial stop losses below the N-period low on longs
Caveats
A single extreme candle — an outlier spike — can stretch the upper or lower channel significantly, delaying breakout signals. In sideways markets, Donchian channels generate frequent false breakouts. The method requires accepting large drawdowns during non-trending periods, trusting that a few large trend-following wins will outweigh many small losses. Mechanical discipline is essential.