Position Size Calculator
Work out exactly how much to buy or sell so that hitting your stop-loss costs a fixed, planned share of your account. Enter your balance, the percentage you are willing to risk, your entry and your stop-loss price.
How to calculate position size
- 01
Decide the share of your account you are willing to lose if the trade hits its stop, for example 1%. That is your amount at risk: balance times risk percent.
- 02
Measure the per-unit risk: the distance between your entry price and your stop-loss price.
- 03
Divide the amount at risk by the per-unit risk. The result is how many units to trade.
Position size = (Balance × Risk%) / |Entry - Stop|
Worked examples
Frequently asked questions
What is position sizing?
Position sizing decides how many units, contracts or lots to trade so that a losing trade costs a fixed, pre-planned amount. It ties your trade size to your account size and your stop distance instead of a round guess.
How much should I risk per trade?
That is a personal choice. Many systematic traders cap the risk on any single trade at a small fixed percentage of the account so no one loss is damaging. This tool lets you plug in whatever percentage you use.
Does leverage change my position size?
No. Your position size comes from your risk and stop distance. Leverage only changes the margin you must post to hold that position, not how large the position should be.
What is the difference between position size and margin?
Position size is the full value of what you control. Margin is the collateral your exchange locks to open it. With 10x leverage a $2,000 position needs about $200 of margin.
Does this work for crypto, forex and stocks?
Yes. The maths is the same across markets. For forex the units are lots and for stocks they are shares, but position size is always the amount at risk divided by the entry-to-stop distance.
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Not financial advice. This calculator is an educational tool, not financial advice. Trading carries substantial risk and you can lose some or all of your capital. Figures are estimates. Verify against your exchange's own margin, fee and liquidation rules before trading.