Position Size Calculator
Size a trade so a stop-out never costs more than a fixed percentage of your account. The single most important habit in risk management.
Position size is capped so a stop-out loses no more than your chosen % of the account.
Educational tool only — not financial advice. Assumes a single instrument with a linear payoff (shares/units); it does not account for fees, slippage, leverage multipliers, or contract sizing. See the full disclaimer.
How it works
Your risk amount is your account size × the percentage you're willing to lose on one trade (most disciplined traders use 0.5–2%). Your risk per unit is the distance from entry to stop-loss. Dividing one by the other gives the largest position that keeps a stop-out within your risk budget. Learn the reasoning in Risk & Expectancy.