How the position size is calculated
- Money at risk = account size × risk per trade. Example: $10,000 × 1% = $100.
- Risk per share = entry price − stop-loss price. Example: $50 − $48 = $2.
- Shares = money at risk ÷ risk per share = $100 ÷ $2 = 50 shares (a $2,500 position).
The number of shares is always rounded down, so the loss at the stop never exceeds the risk you chose. With fractional shares on, it is rounded down to 0.001 of a share — useful when one share costs more than your risk allows. Not every broker offers fractional shares, and some do not accept stop orders for them.
Commissions differ by broker, so you enter your own: a percentage of the order value (for example 0.04%), a fixed amount per order or an amount per share, with an optional minimum per order. The commission is counted on both the buy and the sell at the stop, and the share count is lowered until the total loss stays within your risk. Spreads, currency conversion and taxes are not included.
In dollar-amount mode you enter how much you want to invest, and the calculator shows how many shares that buys and how much you would lose if the stop is hit.