How far the symbol moves per day in dollars on average, the basis for placing a stop-loss.
What it measures
Average True Range (ATR · Average True Range) is the average true range of an asset's movement per session, usually over fourteen sessions and including gaps. It answers one very useful question: how far does this asset typically move in a normal day?
Turning volatility into decisions
It is the natural unit of measurement for everything. A stop tighter than today's range is noise that will certainly get hit, and a session target beyond two ranges is a statistical dream. Professionals set stops in multiples of it (1.5× or 2×) and size positions with it instead of arbitrary numbers.
Sizing positions with it
A sound sizing formula: acceptable risk amount ÷ (range multiple × its value) = number of shares. That equalizes the risk of a trade in a calm stock and a wild one, because the size adapts to each one's nature.
Hypothetical example
A stock at $80 with a daily range of $2.40: a stop at 1.5× means $3.60 per share. Someone willing to risk $720 buys two hundred shares, no more. The number comes from the nature of the asset, not from wishful thinking.
Common mistake
Freezing the range in your head. It widens in stormy periods and shrinks in calm ones, and last month's stop may be noise this month. Read it live with every trade.
Why measure with volatility rather than a fixed percentage
A fixed percentage is unfair to calm assets and too loose for volatile ones: a 2% move is an event in a large index and noise in a young stock. A range derived from volatility calibrates each asset to its own habits, so it sets the stop and the target together instead of one number copied between symbols.
Where to see it on the platform
The trade journal calculates position size from your inputs, and the scanner terminal shows each symbol's daily range among its live stats.
The symbol card shows it for the near term, and the calculator derives it from implied volatility for any horizon you choose.
