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Position size calculator

Position size = (account size × risk %) ÷ (entry price − stop price). If the trade hits your stop, you lose about the amount you chose to risk. With the common 1% rule, a $10,000 account risks $100 per trade.

Account size ($)

Risk per trade (%)

Entry price ($)

Stop-loss price ($)

Target price ($, optional)

Amount at risk–

Risk per share–

Shares to buy–

Position value–

% of account used–

Reward-to-risk–

How position sizing works

Dollar risk = account × risk %. Risk per share = |entry − stop|. Shares = dollar risk ÷ risk per share, rounded down. Position value = shares × entry. Reward-to-risk = |target − entry| ÷ |entry − stop|. Gaps past your stop can make the real loss larger. For futures, use the futures tick value calculator.

Common questions

What is the 1% rule in trading?

Risking no more than 1% of your account on any single trade, so a loss at your stop costs at most 1%.

Why does a tighter stop let me buy more shares?

Risk per share is smaller, so the same dollar risk covers more shares. The position value can get large, so check the % of account used.

Does position sizing guarantee my max loss?

No. Prices can gap past a stop-loss, especially overnight or around news.

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Last reviewed October 31, 2026. This calculator gives estimates for education and planning only. Results depend entirely on the numbers you enter and the assumptions stated on this page; they are not investment, tax or trading advice, and real results will differ.