Position Size Calculator
Calculate a sample stock position size from account size, risk percentage, entry price, and stop-loss price.
Last Updated: May 2026Position Size Formula
Example Position Size Calculation
Suppose an account is $10,000 and the sample risk per trade is 1%. The dollar risk amount is $100.
If the entry price is $50 and the stop-loss price is $45, the risk per share is $5. The sample position size is 20 shares.
- Enter account size.
- Enter the risk percentage for the example.
- Enter entry and stop-loss prices.
- Review the estimated share count and risk amount.
Position Size Comparison Example
Position size changes quickly when stop-loss distance changes. This example uses a $10,000 account and 1% risk per trade.
| Risk Amount | Risk Per Share | Estimated Shares | Trade Value at $50 |
|---|---|---|---|
| $100 | $2 | 50 | $2,500 |
| $100 | $5 | 20 | $1,000 |
| $100 | $10 | 10 | $500 |
How to Interpret the Result
A smaller stop-loss distance allows a larger share count for the same risk amount. A wider stop-loss distance reduces the estimated share count.
The output is a risk model, not a trade recommendation. Real losses can exceed the modeled amount if prices gap or orders execute poorly.
What This Calculator Does Not Include
The calculator does not model slippage, gaps, liquidity, option contracts, margin rules, or broker restrictions.
It rounds share count for a simple stock example. Fractional shares may or may not be available.
How to Use This Calculator
Calculate a sample stock position size from account size, risk percentage, entry price, and stop-loss price.
- Enter realistic values from your own notes or a sample stock scenario.
- Compare the result with the formula section so the calculation is easy to audit.
- Use the result as an educational reference, not as a buy, sell, or hold signal.
Important Limits
Position Size Calculator does not predict market direction, future returns, liquidity, taxes, slippage, or personal suitability. Real results can differ because prices, fees, tax rules, and order execution may change.
Learn the Concepts Behind the Numbers
After using this calculator, use the learning checks to review whether the underlying stock terms, risk ideas, and market basics are clear.
Educational Review
Last updated: May 2026. StockCalcLab tools are built for financial education and calculation practice only. They do not provide personalized financial, tax, legal, or investment advice.
Position Size FAQ
What is position sizing?
Position sizing estimates how many shares fit a sample risk amount and stop-loss distance.
What is risk per share?
Risk per share is the difference between entry price and stop-loss price in this educational example.
Should I round position size?
Many examples round down to whole shares because fractional-share availability depends on the broker.
Does this guarantee limited loss?
No. Real orders can experience gaps, slippage, liquidity issues, and execution differences.
How does stop-loss distance affect position size?
A wider stop-loss distance increases risk per share, which lowers the estimated number of shares for the same account risk amount.
Can I use this as a stock risk calculator?
Yes, it can be used as an educational stock risk calculator because it connects account size, risk percentage, stop-loss distance, and share count.
Disclaimer: This calculator is for educational position sizing examples only and is not trading or investment advice.