Position Size Calculator
Trade with disciplined risk. Enter your capital, the percentage you're willing to risk, your entry and stop-loss, and get the exact quantity, money at risk, position value and reward-to-risk ratio. Calculated in your browser.
How position sizing works
First decide the money you're prepared to lose: risk amount = capital × risk%. Then divide it
by the per-share risk, the distance from entry to stop-loss:
quantity = risk amount ÷ |entry − stop-loss|, rounded down to whole shares. A wider stop means
each share risks more, so you buy fewer shares for the same money at risk. The reward-to-risk ratio,
(target − entry) ÷ (entry − stop), tells you whether the trade is worth taking.
FAQ
How do I calculate position size from risk?
Quantity = (capital × risk% ) ÷ (entry − stop-loss). You first decide how much money you are willing to lose on the trade (your risk amount), then divide it by the per-share risk (the distance from entry to stop-loss). This calculator rounds down to whole shares.
What is a sensible risk per trade?
Many traders risk 1–2% of their capital on a single trade so that a run of losses cannot wipe out the account. Lowering the risk percentage reduces position size and drawdown; this tool lets you test different values instantly.
What is the reward-to-risk ratio?
It compares your potential profit to your potential loss: (target − entry) ÷ (entry − stop-loss). A ratio of 2 means you aim to make twice what you risk. Enter a target price to see the ratio for your trade.
Does position size change with a wider stop-loss?
Yes. A wider stop (larger entry-to-stop distance) means each share risks more, so for the same risk amount you can buy fewer shares. A tighter stop allows a larger position for the same money at risk.
For education only — not investment advice. Position sizing manages risk but does not guarantee outcomes; slippage and gaps can exceed your stop-loss.