Average True Range (ATR) measures volatility - the typical size of a bar's move over a set period. It says nothing about direction. It answers one question: how much does this thing normally move in a given window? That answer is the foundation of intelligent stop placement.

How it's built

"True range" is the largest of: the current bar's high-low, the high versus the prior close, or the low versus the prior close - which captures gaps. ATR averages that over a period (commonly 14 bars). A rising ATR means the market is getting more volatile; a falling ATR means it is calming.

Sizing stops with ATR

A fixed-point stop ignores how volatile the market is right now. A one-point stop that makes sense in a quiet tape gets hit constantly in a fast one. Placing stops as a multiple of ATR adapts to conditions - wider when the market is jumpy, tighter when it is calm - so you are stopped out by a real reversal, not by normal noise.

A stop that ignores volatility isn't a stop - it's a coin flip on getting shaken out.

Volatility as a regime tell

ATR also flags regime shifts. A sudden expansion often precedes or accompanies a trending move; a long contraction (a "volatility squeeze") frequently precedes a breakout. Read alongside the VIX and volume, ATR helps you calibrate how aggressive to be - and how much room a trade needs to breathe.