Position Size Calculator

Position sizing works backwards from the loss you can accept. Decide how much of your account to risk, set a stop-loss, and the calculator tells you how many units to buy or sell so that being stopped out costs exactly that amount. Whether the stop is above or below your entry decides if it is a long or a short.

The formula

Position size = amount at risk ÷ loss per unit at the stop. The loss per unit is the distance between entry and stop, plus any fees you would pay opening and closing.

Worked example

With a 10,000 account risking 1% (100), an entry of 65,000 and a stop at 63,500, each unit loses 1,500 if stopped out. The position size is 100 ÷ 1,500 = 0.0667 units, worth 4,333.33 (0.433 times the account). A take-profit at 68,000 would make 200, which is 2R (twice the amount risked).

Things to know

• Fees raise the loss per unit, so including them gives a slightly smaller position.
• In fast markets a stop can fill beyond its price (slippage), so the real loss can be larger.
• Leverage needed is the position value divided by your account; check your exchange allows it and what its liquidation level would be.