Position size calculator
Position sizing starts from the loss you accept, not from the number of shares you want. Enter your account, the percent you will risk, the entry price and the stop price. The calculator gives the size that makes a stop-out cost exactly that amount.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Enter your account balance and the percent you accept to lose on this trade.
- Enter the entry price and the stop-loss price.
- Optionally enter a target to see the reward-to-risk ratio.
How it works
- Amount at risk = account × risk ÷ 100.
- Units = amount at risk ÷ |entry − stop|; lots = units ÷ units per lot.
- Position value = units × entry price.
- Reward-to-risk = |target − entry| ÷ |entry − stop|.
Worked example
Account 10,000, risk 1%, entry 50, stop 48, target 56. Amount at risk is 100, the stop distance is 2, so the size is 50 units worth 2,500. The target is 6 away: reward-to-risk 3 : 1, profit 300.
Tips
- Many traders keep the risk per trade small; the right level is your choice.
- A wide stop gives a smaller size for the same risk.
- Results are estimates, not financial advice.
Frequently asked questions
How is the position size calculated?
Amount at risk = account × risk percent. Position size = amount at risk ÷ the distance between entry and stop. With 10,000, 1% risk, entry 50 and stop 48 you risk 100 and buy 50 units.
Which currency are the prices in?
The prices must be in your account currency per unit. For a currency pair whose quote currency differs from your account, convert the stop distance first or use the pip value calculator.
What is a lot?
A lot is a standard number of units. Forex brokers often use 100,000 units for a standard lot, but contract sizes vary, so enter the one your broker uses. For shares, leave it at 1.
Does it include fees or slippage?
No. Commissions, spread and slippage add to the loss when a stop is hit, so real losses can be larger than the amount shown.
Is this financial advice?
No. Trading carries risk of loss. This tool only does arithmetic on the numbers you type.