Key points
- Enter account size, risk %, entry price, and stop-loss to get your max share count.
- Built around the classic risk-per-share formula: max risk $ divided by (entry minus stop).
- Add a target price to also see your reward-to-risk ratio, like 2:1 or 3:1.
- Runs entirely in your browser. Nothing you type is saved or sent anywhere.
Position sizing is the part of a trade most people skip, and it's usually the part that matters most. Two traders can buy the exact same stock at the exact same price and end up with completely different outcomes, just because one of them risked 20% of their account and the other risked 2%. This tool does the math for you: tell it your account size, how much you're willing to risk, your entry, and your stop, and it tells you how many shares fit that risk.
For the tickers behind any position you're sizing up, check our filings feed for the latest SEC activity, our earnings calendar for upcoming reports, or the Wire for the latest market news.
Enter an account size, entry price, and a stop-loss price below your entry to see your position size.
How to use this calculator
- Account size: the total dollars in the account you're trading with.
- Risk per trade (%): the share of that account you're willing to lose on this one trade if the stop hits. 1-2% is a common starting point.
- Entry price: the price you plan to buy at.
- Stop-loss price: the price where you'll cut the position if it goes against you. Must be below your entry for a long position.
- Target price (optional): where you'd expect to take profit, to see your reward-to-risk ratio.
This tool is for educational purposes and general planning only. It is not investment advice, and it doesn't account for taxes, commissions, slippage, or your specific financial situation. Always do your own research and consider talking to a licensed financial advisor before trading.
FAQ
How does the position size calculator work?
Enter your account size, how much of your account you're willing to risk on the trade (as a percent), your planned entry price, and your stop-loss price. The calculator finds your risk per share (entry minus stop), divides your max dollar risk by that number, and rounds down to the number of shares you can buy without risking more than your chosen percent if the stop gets hit.
What risk percent per trade should I use?
Many traders risk between 1% and 2% of their account on any single trade, which is why this calculator defaults to 2%. Risking more than that on one position means a short losing streak can do serious damage to an account. This is a common guideline, not a rule, and it isn't investment advice.
What is reward to risk, and what's a good ratio?
Reward to risk compares how much you stand to gain if your target price hits versus how much you stand to lose if your stop hits. A 2:1 ratio means the potential gain is twice the potential loss. Many traders look for at least 1.5:1 to 2:1 before taking a trade, so that a strategy can still be profitable even if it's right less than half the time.
Does this calculator place trades or store my data?
No. It's a plain calculator that runs in your browser. It doesn't connect to any brokerage, doesn't place orders, and doesn't save or send the numbers you type in anywhere.