Position Size Calculator
Enter your account size, risk %, and stop loss — get the exact number of shares or contracts to buy. Works for stocks, crypto, forex, and futures.
Position Size Calculator
How to Calculate Position Size
Position sizing determines exactly how many shares or contracts to buy on every trade. Get it wrong and a single loss can wreck your account. Get it right and you survive long enough to let your edge compound.
This calculator takes three inputs: your account balance, the percentage you're willing to risk per trade, and your stop loss distance. It divides the dollar amount you're risking by the distance to your stop — giving you the exact position size that keeps your risk constant regardless of the setup.
Most traders risk 1-2% per account per trade. At 1% risk on a $25,000 account, you're risking $250 per trade. If your stop loss is $5 away from entry, you buy 50 shares. The math is simple, but doing it manually before every trade is slow and error-prone.
Formula
Position Size = (Account Size × Risk %) ÷ (Entry Price − Stop Loss Price)
Example
You have a $50,000 trading account and risk 1% per trade. You want to buy AAPL at $185 with a stop loss at $180.
Dollar risk = $50,000 × 0.01 = $500. Stop loss distance = $185 − $180 = $5. Position size = $500 ÷ $5 = 100 shares. Total position value = $18,500 (37% of account), but you're only risking $500 (1%).
Frequently Asked Questions
What percentage should I risk per trade?
Most professional traders risk 0.5% to 2% per trade. Beginners should start at 0.5-1% until they have a proven track record. The lower your risk per trade, the more losses you can absorb before blowing your account.
Does position sizing work for crypto and forex?
Yes. The formula is identical — you just adjust for the asset's price and lot sizes. For forex, position size is measured in lots rather than shares. For crypto, it's measured in coins or tokens. This calculator handles all four markets.
What's the difference between position sizing and risk management?
Position sizing IS risk management. It's the mechanism that controls how much capital you expose on every trade. Without consistent position sizing, your risk is random — and random risk eventually blows up accounts.
Should I use the same position size on every trade?
No. Use the same risk percentage, not the same number of shares. A $200 stock with a $10 stop needs fewer shares than a $20 stock with a $1 stop to risk the same dollar amount. The calculator handles this automatically.
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Disclaimer: This calculator is for educational purposes only and does not constitute financial advice. Trading involves substantial risk of loss. Past performance does not guarantee future results. Always do your own research and consult with a licensed financial advisor before making investment decisions.