Stock Tools
Stock Position Size Calculator
Determine how many shares to buy to ensure you only risk a specific percentage of your trading account.
Result
Dollar Risk Allowed: -
Risk Per Share:
Maximum Shares:
Estimated Position Value: -
Risk Management Basics
Position sizing is the most important part of risk management. By calculating shares based on your stop loss, you ensure that if the trade hits your stop, you only lose the exact dollar amount you were willing to risk.
Shares = (Account Size × Risk %) / (Entry Price - Stop Loss Price)
Frequently Asked Questions
What is position sizing?
Position sizing is the process of determining how many shares to buy based on your account size, risk tolerance, and stop loss distance. It is a core component of risk management in trading.
How do I choose my risk percentage?
Most traders risk 0.5% to 2% of their account per trade. Beginners should start on the lower end. Your total portfolio risk depends on how many concurrent positions you hold.
What is the difference between position size and share quantity?
Position size typically refers to the dollar value of the trade. Share quantity is the number of shares purchased. This calculator gives you both: max shares and estimated position value.
Should I include fees in my position size calculation?
Yes — if your broker charges commissions, subtract them from your allowed dollar risk before dividing. This calculator does not include fees, so tighten your risk percentage slightly to account for commission costs.
Can I use this for short selling?
Yes. For short trades, treat the entry price as your sell price and the stop loss as your buy-to-cover price. The risk per share formula works the same way for short positions.