Average True Range (ATR) and Measuring Volatility

Average True Range (ATR) measures the average size of an instrument's price movement over a set number of recent periods (14 is the common default), expressed in the same units as price. A higher ATR means the instrument has been moving in larger swings recently; a lower ATR means it's been relatively calm. Unlike indicators that try to predict direction, ATR says nothing about which way price will go -- only how much it tends to move.

That makes ATR a practical tool for risk management rather than for finding entries. A stop-loss set at a fixed number of pips regardless of conditions can be too tight in a volatile market (getting hit by normal noise) or unnecessarily wide in a calm one. Setting stops and take-profits as a multiple of ATR (for example, 1.5x ATR) automatically adjusts them to current volatility, so the same strategy behaves sensibly whether the market is quiet or wild.

ATR is also used for position sizing: a trader risking a fixed dollar amount per trade can use ATR to work out how many units or lots that fixed risk allows for, given the instrument's current typical range -- a more volatile instrument gets a smaller position for the same dollar risk, and a calmer one gets a larger position, keeping risk consistent across very different markets.

Because ATR only measures magnitude, not direction, it's typically paired with trend or momentum tools (moving averages, MACD, RSI) that supply the directional view, while ATR supplies the sizing and stop-placement logic around it.