Home Tools ATR stop and position size
ATR Stop and Position Size Calculator
Set the stop from how far the stock really moves on an ordinary day, then size the trade so a stop-out costs exactly what you chose to risk.
How it works
Average True Range (ATR) measures how far a stock typically moves in a day, gaps included. A stop set a fixed number of ATRs away gives a calm stock a tight stop and a volatile stock a wide one, so ordinary noise is less likely to knock you out.
The share count then works backward from your risk: shares = dollars at risk ÷ stop distance. A wider stop means fewer shares, so the dollar loss at the stop stays the same whichever stock you trade.
Go deeper
Is two ATRs the right distance? Does an ATR stop beat a fixed percentage, and is the 1% rule right for you? Average True Range tests each rule of thumb on every S&P 500 stock since 1990.
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