One of the most neglected aspects for people starting to invest isn't "what to buy," but "at what point do I admit the idea didn't work and get out." ATR (Average True Range) is a technical tool built exactly for that.
What ATR measures
ATR calculates a stock's average trading range over a period (typically 14 sessions), accounting for gaps between one day's close and the next day's open. In simple terms: how much this stock moves on a "normal" day. A stock with a high ATR is more volatile day to day than one with a low ATR, regardless of its price.
Why use it for a stop-loss instead of a fixed percentage
A common mistake is setting the stop-loss at a fixed percentage (for example, "always 5% below") regardless of the stock. The problem: a stock that normally moves 6-7% on any given day would trigger that stop from simple noise, not because the investment thesis changed. ATR lets you adjust the stop to each stock's actual volatility: on DSMarketLearning, the "suggested stop" is calculated as the current price minus 1.5 times the 14-period ATR — a reference that breathes with each particular stock's normal behavior.
A technical reference, not a recommendation
This calculation is a risk-management tool, not a prediction of where the price is headed. It helps answer, ahead of time, the question "at what point do I recognize I was wrong?" — before in-the-moment emotion makes that decision harder.
This article is educational content, not personalized investment advice. Before making decisions, read our disclaimer.