Trading term
What is Donchian channel?
A Donchian channel plots the highest high and the lowest low of the last N periods as two lines, forming a band around price. Price touching the upper line means it has just made an N-period high — the classic breakout trigger.
The construction could not be simpler. Pick a lookback, usually 20 periods. The upper line is the highest high over that window, the lower line is the lowest low, and a middle line marks the midpoint. Because both lines are drawn from actual extremes, they form flat steps rather than smooth curves, and they only move when a new extreme prints.
That simplicity is the point. Touching the upper channel is, by definition, a 20-day breakout — there is no smoothing, no lag from an average, and nothing to interpret. Richard Donchian pioneered the approach, and it became famous as the core of the Turtle Traders' system in the 1980s, which used a 20-period channel to enter and a shorter 10-period channel in the opposite direction to exit.
A subtlety worth knowing: the channel width itself is a volatility read. In a quiet market the band is narrow and breakouts trigger easily; in a wild one it is wide and only a genuinely large move touches an edge. The indicator adapts to conditions without any extra setting.
The lines are simply the highest high and lowest low of the prior N candles, so they hold flat until a new extreme prints. Touching the upper line IS an N-period breakout.
For example
On a 20-day Donchian channel the upper line sits at $58 — the highest price of the last month. Price prints $58.40, touching the upper channel: a 20-day breakout. A Turtle-style trader buys there and trails the exit at the 10-day low, which at that moment is $53.
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Explore Premium →Why it matters to you
The Donchian channel makes 'breakout' a fact rather than an opinion. A new N-period high either printed or it didn't — no drawing skill, no debate about where the line goes, and nothing to fit after the fact. That objectivity is exactly why it survives as a backtestable rule when most chart patterns don't.
⚠ Most channel breakouts fail
Systems built on this — the Turtles included — typically win on a minority of trades and make their money from a few enormous trends. If you take the entries but not the discipline of cutting the many small losers and running the few big winners, you get the loss rate without the payoff. The indicator is easy; the position sizing and the patience are the actual system.