Position size calculator
It sizes the trade so that hitting your stop-loss costs no more than the share of your account you choose. It works for long and short trades.
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How to use it
- Enter account balance, risk per trade, entry price and stop-loss price.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Risk amount = balance × risk % ÷ 100. Risk per unit = |entry - stop-loss|. Units = risk amount ÷ risk per unit, rounded down.
Example
Inputs: Account balance = 10,000, Risk per trade = 1 %, Entry price = 50, Stop-loss price = 48. Result: Units to trade (whole): 50; Exact units: 50; Amount at risk: 100.00.
Limits and caveats
- Slippage and commissions are not included, and gaps can make the real loss larger than planned.
- With a very tight stop the position value can exceed your balance; check your available margin.
Questions about this tool
What risk percentage is typical?
Many traders keep each trade to 1% to 2% of the account, so a losing streak does not hurt the balance too much.
Why is the count rounded down?
So the loss at your stop does not exceed the amount you set. Rounding up could push it slightly over.
Does it work for short trades?
Yes, put the stop-loss above the entry price and the calculator uses the absolute difference.