Position sizing refers to the number of shares to be purchased for a stock or etf. In previous decades, allocation based on a percentage of your overall portfolio was the rule of thumb. But in this day and edge that is not enough. Your total portfolio size and risk tolerance will be input into a position sizing calculator to properly reflect your situation. Most important though is that the position sizing calculator know the specific risk exposure for a stock or etf. The best way to do this is to utilize SmartStops intelligent calculations. See our How Much to Buy smarter position sizing calculator to learn more.