Position Size Calculator
Calculate the optimal number of shares to buy or sell based on your account size, risk tolerance, and stop loss level. Essential for proper risk management.
Position Parameters
Quick Risk Presets
Recommended Position Size
Risk & Reward Analysis
Price Levels
How Position Sizing Works
Position sizing is a fundamental risk management technique that determines how many shares or contracts to trade based on your account size and risk tolerance. The goal is to limit your loss on any single trade to a predetermined percentage of your portfolio.
Example Calculation
- • Account: $50,000
- • Risk: 2% = $1,000
- • Entry: $150, Stop: $145
- • Risk per share: $5
- • Position: $1,000 ÷ $5 = 200 shares
The 2% Rule
Most professional traders risk no more than 1-2% of their account on any single trade. This means you can have 50 consecutive losing trades before losing your entire account, which is statistically unlikely with a good trading strategy.
Risk Management Best Practices
Do
- ✓ Always use stop losses
- ✓ Calculate position size BEFORE entering
- ✓ Risk consistent percentage per trade
- ✓ Consider total portfolio exposure
- ✓ Aim for 2:1 or better risk/reward
Don't
- ✗ Risk more than 2% per trade
- ✗ Move stops to avoid losses
- ✗ Average down on losing positions
- ✗ Overtrade to recover losses
- ✗ Trade without a plan
Pro Tips
- • Scale into positions gradually
- • Correlate position sizes with conviction
- • Account for slippage and gaps
- • Review and adjust sizing monthly
- • Track your actual vs planned risk
Frequently Asked Questions
What is the best risk percentage for trading?▼
Most professional traders use 1-2% risk per trade. Beginners should start with 1% until they develop a consistent winning strategy. Never risk more than 5% on a single trade, regardless of conviction.
How do I determine my stop loss placement?▼
Stop losses should be placed at technical levels where your trade thesis is invalidated - below support for longs, above resistance for shorts. Avoid placing stops at round numbers where they can be easily triggered by market makers.
What is a good risk/reward ratio?▼
A minimum of 2:1 risk/reward is recommended. This means your potential profit should be at least twice your potential loss. With 2:1 R/R, you only need to win 34% of trades to break even.
Should I use the same position size for every trade?▼
While consistent risk percentage (e.g., 2%) is recommended, position size in shares will vary based on how far your stop loss is from entry. Tighter stops allow larger positions, wider stops require smaller positions.
How does position sizing differ for options vs stocks?▼
For options, risk the same dollar amount but remember options can go to zero. Many traders risk 1% on options trades due to higher volatility. Calculate position size based on the premium paid, not the notional value.
What is the Kelly Criterion for position sizing?▼
The Kelly Criterion suggests optimal bet sizing based on win rate and payoff ratio: Kelly % = W - (1-W)/R, where W is win rate and R is risk/reward. Most traders use 'half Kelly' to reduce volatility.