Position Size Calculator
Work out how large a position to open based on your account size and risk tolerance.
How to use Position Size Calculator
- Enter your account balance and the percentage of it you're willing to risk on this trade.
- Enter your planned entry price and stop-loss price.
- The position size (in units and dollars), dollar risk amount, and leverage required all update instantly.
About this tool
The Position Size Calculator answers a core risk-management question: given how much of your account you're willing to risk on one trade, and where your stop-loss is, how large should your position actually be? It calculates the position size in units and dollars, and how much leverage that position would require relative to your account balance. This is a risk-sizing tool, not a prediction of outcomes — it doesn't guarantee your stop-loss will fill at exactly the price you set.
Frequently Asked Questions
How is position size calculated?
Risk amount = account balance × risk percentage. That's divided by the per-unit risk (the difference between your entry and stop-loss price) to get the position size in units, so that if the stop-loss is hit, you lose exactly your intended risk amount — no more.
What's a reasonable risk percentage per trade?
This varies by strategy and risk tolerance, but many traders risking a small, fixed percentage (often 0.5%-2%) per trade, specifically so that a string of losses doesn't seriously damage the account. This tool doesn't recommend a number — that's a personal risk decision.
What does 'leverage required' mean here?
It's the calculated position's dollar value divided by your account balance. A value under 1x means the position fits within your balance with no leverage needed; above 1x means you'd need at least that much leverage (or margin) to open a position of that size.