Position Size Calculator

A position size calculator answers the most important question before any trade: how many shares can I buy without risking more than I planned? Enter your account size, the percentage you are willing to risk, your entry price, and your stop-loss price. The tool works out the dollars at risk and divides by the per-share risk to give a share count that keeps every trade to the same fixed risk — the foundation of consistent risk management.

Account size ($) Risk per trade (%) Entry price ($) Stop-loss price ($)

Dollars at risk —

Risk per share —

Position size (shares) —

Runs entirely in your browser. Nothing is sent or stored.

Related metrics

R-Multiple Expectancy Maximum Drawdown

Frequently asked questions

How is position size calculated? +

Dollars at risk = account size × risk %. Shares = dollars at risk ÷ |entry − stop|, rounded down so you never exceed your planned risk.

What risk percentage should I use? +

Many traders cap risk at 0.5%–2% of the account per trade. The right number depends on your strategy and tolerance; this tool lets you test any value.