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Position Size Calculator

Figure out exactly how many shares to buy so a single trade only risks what you decide it should. Enter your account size, the percent you're willing to risk, your entry price, and your stop-loss, this free calculator returns your share count, dollar risk, and total position value instantly.

How it works

First it works out the most you'll risk on the trade: dollar risk = account size × risk %. With a $10,000 account and 1% risk, that's $100.

Next it measures your risk per share, which is the distance between your entry and your stop-loss: |entry − stop|. Buying at $50 with a stop at $48 means $2 of risk per share.

Then shares = dollar risk ÷ risk per share (rounded down). $100 ÷ $2 = 50 shares. Your total position value is shares × entry price, or $2,500 here. Sizing this way keeps every loss the same small slice of your account no matter the stock's price.

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Educational tool. Not investment advice. JagSim is a simulator, not a broker.

Last updated: July 2026