Position Size Calculator
How many shares to buy for a fixed dollar risk.
Shares to buy
50
Risk per share $5, total risk $250
Position value
$7,500
Percent of account
30.0%
Shares are floored to whole numbers. The classic 1% rule keeps any single loss small enough that a streak does not wreck the account.
About
Pro traders size positions by risk, not by dollar amount. If you'll bail at $X stop loss and want to risk $Y on the trade, this tells you exactly how many shares to buy.
How to use
- Enter your account size and risk per trade (1-2% is typical).
- Enter the entry price and stop loss.
- See the share count and total position value.
FAQ
What's a sensible risk per trade?+
1-2% is the textbook range. At 2% you can lose 10 trades in a row and still have 80% of your account. Day traders sometimes go 0.5% to allow more setups.
Does it account for slippage?+
No. Slippage on stops is usually 0.5-1% in liquid stocks, more in small caps. Build it into your stop placement, not the position size.